The value of the physiological minimum protein in medical terms. The role of proteins in nutrition, norms, nitrogen balance, wear coefficient, physiological protein minimum. Skin deficiency physiological minimum protein for adults
The protein minimum is the minimum amount of protein that allows you to maintain a nitrogen equilibrium in the body (nitrogen is a very important element for all living beings, since it is part of all amino acids and proteins). It has been established that during starvation for 8 to 10 days in the body, a constant amount of protein is split - approximately 23.2 grams (for a person with a mass of 70 kg). However, this does not mean that the admission of the same amount of protein will fully meet the needs of our body in this nutrition component, especially when sports. The protein minimum is capable only to maintain the main physiological processes at the proper level, and that is very short time.
Protein optimum is such a quantity of protein in food, which fully meets the needs of a person in nitrogenous compounds and thereby provides the necessary components that are restored after performing physical dimensions of the muscle, maintains the high performance of the body, contributes to the formation of a sufficient level of resistance to infectious diseases. Protein optimum for the body of an adult woman is about 90 - 100 grams of protein per day, and with regular intensive practices, this sport can increase significantly - up to 130 - 140 grams per day and even more. It is believed that to perform a protein optimum per day when performing physical exercises for each kilogram of body weight, an average of 1.5 grams of protein and above are required. However, even with the most intensive modes of training in exercise, the amount of protein should not exceed 2 - 2.5 grams per kilogram of body weight. If you visit sports sections or fitness clubs with a purely wellness target, the optimal content of the protein in your diet should be considered its number that provides an admission to the body of 1.5 - 1.7 grams of proteins per kilogram of body weight.
However, the observance of a protein minimum and protein optimum during sports is not the only condition for full nutrition, providing rehabilitation processes in the body after active workouts. The fact is that food proteins can differ significantly in their nutritional value. For example, proteins of animal origin are optimal for the human body in their amino acid composition. They contain all the indispensable amino acids necessary for growth and rapid recovery of performance. muscular fabric When practicing sports. The proteins contained in vegetable food contain a very small amount of some essential amino acids or are characterized by the complete absence of some of them. Therefore, when practicing sports is optimal, the diet will be in which meat and dairy products, eggs and fish are necessarily included.
The role of proteins in nutrition, norms, nitrogen balance, wear coefficient, physiological protein minimum. Protein deficiency.
Azoty Balance- the difference between the amount of nitrogen coming from food, and the amount of nitrogen released (mainly in the form of urea and ammonium salts). If the amount of nitrogen incoming nitrogen is the number of allocated, then comes nitrogen equilibrium.This condition is a healthy person with normal nutrition. A nitrogen balance can be positive (nitrogen goes more than derived) in children, as well as patients recovering after heavy diseases. A negative nitrogen balance (nitrogen release prevails over its intake) is observed when aging, starvation and during heavy diseases. With a shipless diet, a nitrate balance becomes negative. Compliance with such a diet during the week leads to the fact that the amount of nitrogen released is ceased to increase and stabilizes about 4 g / days. Such a nitrogen is contained in 25 g of protein. So, with protein starvation per day in the body, about 25 g of own fabric proteins is consumed. The minimum number of proteins in the feed needed to maintain a nitrogen equilibrium corresponds to 30-50 g / CYT, the optimal amount with an average physical activity is ~100-120 g / day.
Norms protein in nutrition.
To maintain a nitrogen equilibrium, it is enough to use 30-50 g of proteins per day. However, such a quantity does not ensure the preservation of human health and health. Adopted protein nutritionals for adults and children take into account climatic conditions, profession, working conditions and other factors. An adult man with an average physical activity should receive 100-120 g of proteins per day. With severe physical work, this rate increases to 130-150. Children up to 12 years old are enough 50-70 g of proteins per day. At the same time it is understood that I writing a variety of animal and vegetable proteins.
Protein deficiency
It is known that even a long exception from the fatter of the human fat or carbohydrates does not cause severe health disorders. However, shipless food (especially prolonged) causes serious exchange violations and inevitably ends with the death of the body. The exception of even one indispensable amino acid from the edible diet leads to the incomplete absorption of other amino acids and is accompanied by the development of negative nitrogenous balance, exhaustion, stopping growth and impairment of the functions of the nervous system. Specific manifestations of the insufficiency of one of the amino acids were detected in rats, which fought proteins devoid of a certain amino acid. So, in the absence of cysteine \u200b\u200b(or cystine), acute liver necrosis occurred, histidine - cataract; The absence of methionine led to anemia, obesity and cirrhosis of the liver, baldness and hemorrhages in the kidneys. The exclusion of lysine from the diet of young rats was accompanied by anemia and sudden death (this syndrome was absent in adult animals).
The deficiency of protein food leads to the disease - "quashoror", which means "gold (or red) boy". The disease develops in children who are deprived of milk and other animal proteins, and eat exclusively vegetable food, including bananas, tarot, millet and, most often, corn. Kvashiorkor is characterized by a height delay, anemia, hypoproteinemia (often accompanied by edema), fat rebirth of the liver. Persons of the Negroid race, the hair acquire a red-brown tint. Often, this disease is accompanied by the atrophy of the pancreatic cells. As a result, the secretion of pancreatic enzymes is disturbed and even a small amount of proteins that comes with food is not absorbed. The kidney damage occurs, as a result of which the excretion of free amino acids with urine increases dramatically. Without treatment, death mortality is 50-90%. Even if children survive, long-term protein failure leads to irreversible violations of not only physiological functions, but also mental abilities. The disease disappears with the timely translation of the patient on a rich protein diet, including large amounts of meat and dairy products. One of the ways to solve the problem is to add lysine preparations.
2. Digestion of proteins in the gastrointestinal tract. Characteristics of peptidase of the stomach, the formation and role of hydrochloric acid.
IN food products The content of free amino acids is very small. The overwhelming amount is included in the proteins that are hydrolyzed in the gastrointestinal tract under the action of protease enzymes (pepticzrolas). The substrate specificity of these enzymes is that each of them, with the highest speed, whipping peptide bonds formed by certain amino acids. Proteases, hydrolyzing peptide bonds inside the protein molecule, are attributed to the Endopeptidase group. Enzymes belonging to the exopeptidase group hydrolyze the peptide bond formed by end amino acids. Under the influence of all proteases, food seats are disintegrated into individual amino acids, which then come into tissue cells.
The formation and role of hydrochloric acid
The main digestive function of the stomach lies in the fact that the protein digestion begins in it. An essential role in this process plays hydrochloric acid. Proteins entering the stomach stimulate the selection histamineand groups of protein hormones - gastrin, which, in turn, cause secretion of NSI and Propriment - pepsinogen. NSI is formed in the shepherd cells of gastric glands during reactions.
The source of H + is H 2 C 3, which is formed in the shelling cells of the stomach from CO 2, diffusing from the blood, and H 2 o under the action of carboanhydrase enzyme (carbonatedehydra-thais):
H 2 O + CO 2 → H 2 CO 3 → NSO 3 - + H +
The dissociation H 2 CO 3 leads to the formation of a bicarbonate, which involving special proteins is released into a plasma in exchange for C1 - and H + ions, which come into the lumen of the stomach by active transport, catalyzed by the membrane H + / K + -atf-aza. At the same time, the concentration of protons in the lumen of the stomach increases by 10 6 times. Ions C1 - come into the lumen of the stomach through the chloride canal.
The concentration of HCl in the gastric juice can reach 0.16 m, due to which the pH value decreases to 1.0-2.0. The technique of protein food is often accompanied by alkaline urine release due to the secretion of a large amount of bicarbonate in the process of formation of HCl.
Under the action of NCLs, denaturation of food proteins that are not subjected to heat treatment, which increases the availability of peptide bonds for proteases. NCl has a bactericidal effect and prevents pathogenic bacteria to the intestines. In addition, hydrochloric acid activates pepsinogen and creates the optimum pH for the action of pepsin.
· Related hydrochloric acid- HCL, associated with proteins and foods of their digestion. The values \u200b\u200bof the associated HCL in healthy people - 20-30 those.
· Free nsl- hydrochloric acid, not associated with the components of the gastric juice. The values \u200b\u200bof free HCL are normal - 20-40 those. pH of the gastric juice is normal -1,5-2,0.
Characteristics of the peptidase of the pancreas and the small intestine. Protection of cells from the action of peptidase.
Fig. 9-23. Ways of biosynthesis of replaceable amino acids.
Amida Glutamine and Asparaginsynthesized from the corresponding dicarboxylic amino acids of the PLA and ASP (see scheme A).
- Serineit is formed from the 3-phosphoglycerate - an intermediate product of glycolysis, which is oxidized to 3-phospopies and then transumens with the formation of se-rin (see scheme b).
- Exists 2 Glycine synthesis paths:
1) from a serine with the participation of the derivative folic acid As a result of the operation of se-rinoximeththransferase:
2) as a result of the action of the enzyme glycinsintase in the reaction:
- Prolineit is synthesized from glutamate in the circuit of reversible reactions. The same reactions are used in catabolism of the spill (see the scheme in with. 494).
In addition to the eight listed replaceable amino acids, four more amino acids can be synthesized in the human body.
Partially replaceable APR and GIS amino acids Synthesized with a difficult way in small quantities. Most of them must come with food.
- Arginine synthesis occurs in the reactions of the ornithic cycle (see above subsection IV);
- Gistidine is synthesized from ATP and Ribose. Part of the hyventidine imidazole cycle - N \u003d CH-NH- is formed from an adenine purin core, the source of which is ATP, the remaining part of the molecule is from the ribose atoms. At the same time, 5-phosphoribosylamine is formed, which, in addition to the hystidine synthesis, is necessary for the synthesis of purines.
For synthesis conditionally replaced amino acids of tyrosine and cysteinean indispensable amino acids of phenylalanine and methionine, respectively (see subsections VIII and IX).
Fig. 9-22. The inclusion of a bezotic residue of amino acids in the common catabolism path.
gloundogenesis process. Such amino acids belong to the group glycogenic amino acids.
Some amino acids in the process of catabolism are converted to acetoacetate (Liz, Leu) or acetyl-coolas and can be used in the synthesis of ketone bodies. Such amino acids are called ketogenic.
Amino acids are used for the synthesis of glucose, and for the synthesis of ketone bodies, since in the process of their catabolism, 2 products are formed - a certain metabolite of the citrate cycle and acetoacetate (three, hairdryer, tire) or acetyl-koa (ile). Such amino acids are called mixed, or glycochetogenic(Fig. 9-22, Table. 9-5).
Anaplerotic reactions
Azyazotic amino acid residues are used to replenish the amount of metabolites of the common catabolism, which is spent on the synthesis of biologically active substances. Such reactions are called anaplerotic. Figure 9-22 highlighted five anaplerotic reactions:
The firth enzyme (coenzyme - biotin), catalyzing this reaction, is detected in the liver and muscles.
2. Amino acids → Glutamate → α-ketoglutarat
The transformation occurs in many tissues under the action of glutamate dehydrogenase or aminotransferase.
3. 
Propionyl-CoA, and then succinyl-cola can also be formed during the decay of higher fatty acids with a nonperative number of carbon atoms (see section 8).
4. Amino acids → Fumarat
5. Amino acids → Oxaloacetate
Reactions 2, 3 occur in all tissues (except liver and muscles), where there is no piruvataturboxylase, and the reactions 4 and 5 are mainly in the liver. Reactions 1 and 3 (Fig. 9-22) - major anaplerotic reactions.
L-amino acid oxidase
Enzyme detected in the liver and kidneys oxidase L-amino acidsable to deamine some L-amino acids (see the diagram at the end page).
The coenfer is FMN in this reaction. However, the contribution of L-amino acid oxidase into deamination is obviously insignificant, since its optimum is under the alkaline medium (pH 10.0). In cells, where the pH of the medium is close to neutral, the activity of the enzyme is very low.
Oxidase D-amino acidsalso found in the kidneys and liver. This is a FAD-dependent enzyme. The optimum pH of this oxidase lies in the neutral medium, so the enzyme is more active than L-amino acid oxidase. The role of d-amino acid oxidase is small, since the number of d-isomers in the body is extremely small, because in the proteins of food and proteins of human and animals, only natural L-amino acids enter. Probably, the oxidase D-amino acids contributes to their transformation into the corresponding L-isomers (Fig. 9-8).
10. Transignment: Process scheme, enzymes, biorol. Adat Biorol and Asat and the clinical significance of their serum determination.
Transministration
Transamination is the reaction of the transfer of α-amino group with amino acids to α-ketokislot, as a result of which a new ketok acid and a new amino acid is formed. The equilibrium constant for most such reactions is close to one (to p ~ 1.0), so the transamination process is easily reversible (see scheme a).
The reactions catalyze aminotransferase enzymes, which serves pyridoxalphosphate (PF) - Vitamin T Derivalent of 6 (pyridoxine, see section 3) (see scheme b).
Aminotransferase found both in the cytoplasm and in the mitochondria of eukarot cells. And mitochondrial and cytoplasmic forms of enzymes differ in physico-chemical properties. In human cells, more than 10 aminotransferase were found, differing in substrate specificity. Almost all amino acids can enter into the transministration reaction with the exception of lysine, threonine and proline.
Scheme A.
Reaction mechanism
Aminotransferase is a classic example of enzymes catalyzing reactions flowing through the Ping-Pong mechanism (see section 2). In such reactions, the first product must escape from the active center of the enzyme before the second substrate can join it.
The active form of aminotransferase is formed as a result of the addition of pyridoxalphosphate to the amino group of lysine with a sturdy anldimine bond (Fig. 9-6). The lysine in position 258 is part of the active center of the enzyme. In addition, ionic bonds are formed between the enzyme and pyridoxalphosphate with the participation of charged atoms of phosphate residue and nitrogen in the pyridine ring of the coenzyme.
The sequence of transamination reactions is presented below.
- In the first stage to pyridoxalphosphate in the active center of the enzyme with an anldimy communication, an amino group from the first substrate - amino acids is joined. The complex of enzyme-pyridoxes-min phosphate and ketokislo is formed - the first product of the reaction. This process includes an intermediate formation of 2 sheffed bases.
- In the second stage, the Pyridoxamine phosphate enzyme complex is connected to the ketokislot (second substrate) and again through intermediate formation 2 of the sheffed bases transmits an amino group to ketokislot. As a result, the enzyme returns to its native form, and a new amino acid is formed - the second product of the reaction. If the aldehyde pyridoxalphosphate group is not occupied by the amino group of the substrate, then it forms Schiffovo base (aldimith) with a ε-amino group of lysine radical in the active center of the enzyme (see the scheme with. 471).
Ornithine cycle
Urea - the main end product of nitrogen exchange,as part of which from the body, up to 90% of the total nitrogen is distinguished (Fig. 9-15). The excretion of urea is normal amounts to ~25 g / day. With increasing the number of proteins consumed, the excretion of urea increases. The urea is synthesized only in the liver, which was installed in the experiments of I.D. Pavlova. The lesion of the liver and violation of urea synthesis leads to an increase in blood content and ammonia tissues and amino acids (first of all, glutamine and alanine). In the 40s of the 20th century, the German biochemists of Krebs and K. Itzelite found that urea synthesis is a cyclic process consisting of several stages, the key connection of which closed the cycle is ornithine. Therefore, the process of synthesis of urea received a name "Ornithine cycle",or "Crec-Generated Cycle".
Urea synthesis reactions
Urea (carbamide) - a complete amide of coalic acid - contains 2 nitrogen atoms. Source of oneof them is ammonia,which in the liver is associated with carbon dioxide with the formation of carbamoyl phosphate under the action of carbamoylphosphatetase I (see the scheme a below).
In the following reaction, the arginosucinatsintytase binds citrulline with aspartate and forms arginosuccinate (arginic acid acid). This enzyme needs Mg 2+ ions. The reaction is spent 1 mol ATP, but the energy of two macroeergic ties is used. Aspartate - the source of the second nitrogen atom of urea(See diagram A on p. 483).
Arginine is subjected to hydrolysis under the action of arginase, while ornithine and urea are formed. Arginase cofactors are ions Ca 2+ or Mn 2+. High concentrations of ornithine and lysine, which are structural analogues of arginine, suppress the activity of this enzyme:
Total urea synthesis equation:
CO 2 + NH 3 + Aspartate + 3 ATF + 2 H 2 O → Urea + Fumarate + 2 (ADF + H 3 P0 4) + AMP + H 4 P 2 O 7.
Ammonia used by carbamoylphosfatsintase I is supplied to the liver with blood-vein blood. The role of other sources, including sensitive deamination of glutamine etats in the liver, is significantly less.
Aspartate required for the synthesis of arginocynate is formed in the liver by transministration
alanine with oxaloacetate. Alanya comes mainly of muscles and intestinal cells. The source of oxaloacetate necessary for this reaction can be considered the conversion of fumaranta formed in the reactions of the ornithine cycle. Fumarate as a result of the two reactions of the citrate cycle turns into an oxaloacetate, from which aspartate is formed by transamination (Fig. 9-17). Thus, with the ornithin cycle conjugate aspartate Regeneration Cycle from Fumarate.Fir VAT formed in this cycle of alanine is used for glukegenesis.
Another source of aspartate for the ornithin cycle is the transamination of glutamate with oxaloacetate.
Albinism
The cause of the metabolic disorder is a congenital defect of tyrosinase. This enzyme catalyzes the conversion of tyrosine into the dof in melanocytes. As a result of the tyrosinase defect, the synthesis of melanin pigments is disturbed.
Clinical manifestation of albinism (from lat. albus -white) - no pigmentation of the skin and hair. Patients often reduced visual acuity, light-friendly occurs. Prolonged stay of such patients under the open sun leads to skin cancer. Frequency of the disease 1:20 000.
Phenylketonuria
In the liver of healthy people, a small part of the phenylalanine (~10%) turns into phenyl lactate and phenylacetylglutamine (Fig. 9-30).
This path of catabolism of phenylalanine becomes the main way in violation of the main path - the conversion to tyrosine, catalyzed by phenyl-alannhydroxylase. Such a violation is accompanied by hyperphenylalanineine and an increase in the blood and urine of the content of metabolites of an alternative path: phenylpiruvat, phenylacetate, phenyllactate and phenylacetylglu-tamin. The phenylalanine hydroxylase defect leads to the disease of phenylketonuria (FKE). Select 2 forms of FCU:
· Classical FKU- The hereditary disease associated with mutations in the phenylalannine hydroxylase gene, which lead to a decrease in the activity of the enzyme or its full inactivation. At the same time, the concentration of phenylalanine increases in blood at 20-30 times (normal - 1.0-2.0 mg / dl), in the urine - 100-300 times compared with the norm (30 mg / dl). The concentration of phenylpiruwate and phenyllactate in the urine reaches 300-600 mg / dl with a complete absence in normal.
· The most severe manifestations of FCU - a violation of mental and physical development, convulsive syndrome, impaired pigmentation. In the absence of treatment, patients do not live up to 30 years. The frequency of the disease is 1:10,000 newborns. The disease is inherited by autosomal recessive type.
· The heavy manifestations of the FCU are associated with the toxic effect on the brain cells of high concentrations of phenylalanine, phenylpiruvat, phenyllactate. The large concentrations of phenylalanine are limited to Tyrosine and tryptophan transport through the blood-brain barrier and inhibit the synthesis of neuro-mediators (dopamine, norepinephrine, serotonin).
· Optional FKU(Correced-dependent hyperphenylalaninemia) is a consequence of mutations in genes controlling metabolism H 4 bp. Clinical manifestations are close, but not exactly coinciding with the manifestations of classical FCU. The frequency of the disease is 1-2 cases per 1 million newborns.
· H 4 BP is necessary for hydroxylation reactions not only phenylalanine, but also tyrosine and tryptophan, therefore, with the lack of this coenzyment, the metabolism of all 3 amino acids, including the synthesis of her-diamediators, is disturbed. The disease is characterized by severe neurological disorders and early death ("malignant" FCU).
Progressive violation of mental and physical development in children, patients with FCU, can be prevented by a diet with a very low content or complete exception of phenylalanine. If such treatment has begun immediately after the birth of the child, the brain damage is prevented. It is believed that restrictions in nutrition can be weakened after 10 years of age (the end of the processes of myelinization-ration of the brain), but at present, many pediatricians are inclined towards "lifelong diet".
For the diagnosis of FCU, high-quality and quantitative methods of detecting pathological metabolites in the urine, determination of the concentration of phenylalanine in the blood and urine. The defective gene is responsible for phenylketonuria, one can detect in phenotypically normal heterozygous media using a phenylalanine tolerance test. To do this, the examined is allowed on an empty stomach ~10 g of phenylalanine as a solution, then blood samples are taken after time intervals, in which the tyrosine content is determined. Normally, the concentration of tyrosine in the blood after the phenylalanine load is significantly higher than that of the heterozygous carriers of the formalketonurium gene. This test is used in genetic advice to determine the risk of birth of a sick child. A screening scheme has been developed to identify newborns with FCU. The test sensitivity practically reaches 100%.
The structure of heme
Gem consists of a bivalent iron ion and porphyrin (Fig. 13-1). Porphin is based on Porphin Structures. Porphine is four pyrrole rings, interconnected by swelling bridges (Fig. 13-1). Depending on the structure of the substituents in the rings of pyrrolas, several types of porphyrins are distinguished: protoporphyrins, etiphrins, meso-porphyrins and coil apartments. Protoporphirins are the predecessors of all other types of porphyrins.
The hemes of different proteins may contain different types of porphyrins (see section 6). In the theme of hemoglobin there is a protoporphyrine IX, which has 4 metal, 2 vinyl radicals and 2 propionic acid residues. The iron in the subject is in the restored state (Fe +2) and is associated with two covalent and two coordination bonds with nitrogen atoms of pyrrole rings. When iron oxidation, gem turns into hematin (Fe 3+). The greatest amount of hem contains erythrocytes filled with hemoglobin, muscle cells having Mioglobin, and liver cells due to the high content of cytochrome p 450.
Regulation of Gema biosynthesis
The regulatory reaction of the synthesis of the heme catalyzes the pyridoxal-dependent enzyme of aminolevulinatsintase. The reaction rate is adjusted altoceptively at the level of enzyme broadcast.
Alosteric inhibitor and the coordinator of the synthesis of aminolevulinatsintase is gem (Fig. 13-5).
In reticulocytes, the synthesis of this enzyme at the broadcast stage adjusts the iron. At the site of the initiation of mRNA encoding the enzyme, there is
Fig. 13-5. Regulation of hem and hemoglobin synthesis. Gem on the principle of negative feedback Inhibits aminolevulinatsintase and aminolevulinatdehydrate and is an inducer of the transition of α- and β-chains of hemoglobin.
the sequence of nucleotides forming a spiker loop, which is called a ferrous-sensitive element (from English, iron-Responsive Element,IRE) (Fig. 13-6).
At high concentrations of iron in cells, it forms a complex with the residues of cysteine \u200b\u200bregulatory-binding protein. The interaction of iron with a regulatory iron binding protein causes a decrease in the affinity of this protein to an IRE element of mRNA encoding aminolevulinatsintase, and continued broadcast (Fig. 13-6, a). At low iron concentrations, the iron binding protein is attached to the iron-sensitive element located on 5 "-th-sensitive end of mRNA, and the transmission of aminolevulinatsintase is inhibited (Fig. 13-6, b).
AminolevulinTehydrates is also altohematically inhibited by gem, but since the activity of this enzyme is almost 80 times higher than the activity of aminolevulinatsyntase, it does not have a large physiological value.
The deficiency of pyridoxalphosphate and drugs, which are its structural analogues, reduce the activity of aminolevulinatsintase.
Synthesis of Bilirin
In the RPC cells, the hemoglobin is oxidized by molecular oxygen. The reactions consistently breaks the methine bridge between the 1st and 2nd pyrrole rings of the hem with their restoration, the cleavage of iron and the protein and the formation of the orange pigment of the bilirubin.
Bilirubin- Toxic, fat soluble substance, capable of disrupting oxidative phosphorylation in cells. Nervous tissue cells are especially sensitive.
Bilirin bias
From the cells of the reticulo-endothelial system of bilirubin enters the blood. Here it is in the complex with albuminplasma, in much smaller quantities - in complexes with metals, amino acids, peptides and other small molecules. The formation of such complexes does not allow to allocate bilirubin with urine. Bilirubin in complex with albumin is called free(non-conjugated) or indirectbilirubin.
What is direct and indirect bilirubin?
Bilirubin serum is divided into two fractions (varieties): direct and indirect, depending on the result of a laboratory reaction with a special reagent (diazoreacive). Indirect bilirubin is toxic bilirubin, which has recently formed from hemoglobin and has not yet contacted the liver. Direct bilirubin is bilirubin, neutralized in the liver and prepared for withdrawal from the body.
28. Jaundie
In all cases, the content of bilirubin in the blood rises. When a certain concentration is reached, it diffuses in the tissue, staining them in yellow color. The yellowing of the tissues due to the deposit in them is bilirubin called jaundice.Clinically jaundice may not manifest as long as the concentration of bilirubin in the blood plasma will exceed the upper limit of the norm by more than 2.5 times, i.e. It will not be higher than 50 μmol / l.
Yellowee newborn
A frequent variety of hemolytic jaundice of newborns is "physiological jaundice", observed in the first days of the child's life. The reason for increasing the concentration of indirect bilirubin in the blood is the accelerated hemolysis and insufficiency of the function of proteins and liver enzymes responsible for the absorption, conjugation and secretion of direct bilirubin. The newborn not only reduced the activity of UDF-glucuronyltransferase, but also, apparently, the synthesis of the second substrate of the reaction of the UDF glucuronate conjugation reaction is not active.
It is known that UDF glucuronlontransferase is an enzyme induced (see section 12). The newborn with a physiological jaundice is introduced a drug phenobarbital whose inductive action was described in section 12.
One of the unpleasant complications of the "physiological jaundice" is bilirubinic encephalopathy. When the concentration of non-conjugated bilirubin exceeds 340 μmol / l, it passes through the hematorecephalic brain barrier and causes its defeat.
Microsomal oxidation
Microsomal oxidases - enzymes localized in the membranes of a smooth ER functioning in a complex with two mini-chondric CPEs. Enzymes catalyzing the restoration of one atom of the molecule O 2 to the formation of water and the inclusion of another oxygen atom into an oxidized substance, obtained the name of microsomal oxidases with a mixed function or microsomal monooxygenases. The oxidation involving monooxygenases is usually studied using microse preparations.
Functioning of cytochrome R 450It is known that molecular oxygen in triplet state inert and is not able to interact with organic compounds. To make oxygen reactive, it is necessary to turn it into a singlet using enzyme system recovery systems. Such is the monoxygenase sishema, containing cytochrome P 450. Binding in the active center of cytochrome p 450 lipophilic substance RH and oxygen molecules increases the oxidative activity of the enzyme.
One oxygen atom takes 2 e and enters the form of 2-. The electron donor serves as NADPH, which is oxidized by the NADPH cytochrome P 450 reductase. O 2- interacts with protons: O 2- + 2N + → H 2 O, and water is formed. The second atom of the oxygen molecule turns on to the substrate Rh, forming a hydroxyl group of substance R-OH (Fig. 12-3).
The total equation of the hydroxylation reaction of the substance Rh enzymes of microsomal oxidation:
RH + O 2 + NADPH + H + → ROH + H 2 O + NADP +.
Substrates P 450 may be many hydrophobic substances as exogenous (drugs, xenobiotics) and endogenous (steroids, fatty acids, etc.) of origin.
Thus, as a result of the first phase of neutralization with the participation of cytochrome P 450, there is a modification of substances to form functional groups that increase the solubility of the hydrophobic connection. As a result of the modification, it is possible to loss the molecule of its biological activity or even the formation of a more active compound than the substance from which it was formed.
Education and neutralization of N-cresol and phenol
Under the influence of the enzymes of bacteria from tyrosine amino acids, phenol and cresol can be formed by the destruction of the side chains of amino acids by microbes (Fig. 12-9).
Successful products on a portal vein enroll in the liver, where the neutralization of phenol and cresol can occur by conjugation with the sulfuric acid residue (FAFS) or with glucuronic acid as part of UDF glucuronate. The reactions of the conjugation of phenol and cresol with FAFS catalyzes the sulfotransfer-times enzyme (Fig. 12-10).
The conjugation of glucuronic acids with phenol and cresol is occurring with the participation of the UDF-glucroonylTransferase enzyme (Fig. 12-11). Conjugation products are well soluble in water and are removed with urine through the kidneys. Increasing the number of glucuronic acid conjugates with phenol and croins are found in the urine while increasing the products of rotten rotation in the intestine.
Fig. 12-8. Neutralization of benzanttracene. E 1 - the enzyme of the microsomal system; E 2 - epoxydhydrate.
Education and neutralization of indole and scatol
In the intestine from the amino acid tryptophan microorganisms form indole and scatol. Bacteria destroy the side chain of tryptophan, leaving the unspoiled ring structure.
Indol is formed as a result of cleavage of lateral chain bacteria, possibly in the form of a serine or alanine (Fig. 12-12).
Skatol and indole are neutralized in the liver in the 2 stages. First, as a result of microsomal oxidation, they acquire a hydroxyl group. Thus, indole turns into indoxyl, and then reacts a conjugation with FAFS, forming an indexyluric acid, the potassium salt of which was called an animal indication (Fig. 12-13).
D. Induction of protective systems
Many enzymes involved in the first and second disposal phase are proteins induced. Even in ancient times, Tsar Mithridat knew that if he could take small doses of poison, you can avoid acute poisoning. The "Mithridate Effect" is based on the induction of certain protective systems (Table 12-3).
In the membranes of the vehicles of cytochrome p 450 contains more (20%) than other membrane-bound enzymes. The drug substance phenobarbital activates the synthesis of cytochrome P 450, UDF glucuronyltransferase and hydrolase epoxy. For example, in animals that were injected with a phenobarbital inductor, an ER membrane area increases, which reaches 90% of all membrane cell structures, and, as a result, an increase in the number of enzymes involved in the neutralization of xenobiotics or toxic substances of endogenous origin.
With chemotherapy of malignant processes, the initial efficiency of the medication often falls. Moreover, multiple drug stability is developing, i.e. stability not only to this therapeutic drug, but also a number of other medicines. This is because antitumor medicines induce the synthesis of p-glycoprotein, glutathioneransferase and glutathione. The use of substances inhibiting or activating the synthesis of p-glycoprotein, as well as the enzymes of glutathione synthesis, increases the efficiency of chemotherapy.
Metals are the inductors of glutathione synthesis and low molecular weight protein of metallotioneen, having SH-groups that can bind them. As a result, the stability of the cell cells to poisons and medicines is increasing.
Increasing the number of glutathioneransferase increases the body's ability to adapt to increasing pollution of the external environment. The induction of the enzyme explains the absence of an anticarcinogenic effect when using a number of medicinal substances. In addition, glutathionisferase synthesis inductors are normal metabolites - sex hormones, yodthnic and cortisol. Catechol-amines through adenylate cyclase system phosphorylate glutathioneransferase and increase its activity.
A number of substances, including drugs (for example, heavy metals, polyphenols, glutathione s-alkyl, some herbicides), inhibit glutathioneransferase.
37. Conjugation - Second Phase Neutralization of Substances
The second phase of the neutralization of substances - the reaction of the conjugation, during which the functional groups are attached to the functional groups in the first stage, other molecules or groups of endogenous origin, which increase the hydrophilicity and canxicity of xenobiotics (Table 12-2).
UDF glucuronelTransferase
Localized main uridine-diphosphate (UDF) -HurdinylTransferase connect the residue of glucuronic acid to the substance molecule formed during the micro-oxidation (Fig. 12-4).
In general, the reaction with the participation of UDF glucuronlontransferase is written as follows:
ROH + UDF-C 6 H 9 O 6 \u003d RO-C 6 H 9 O 6 + UDF.
Sulfotransferase
Protein minimum the smallest amount of protein in food required to preserve nitrogenous equilibrium (see a nitrogen equilibrium) in the body. Reducing the protein in food below B. m. Leads to the decay of its own proteins of the body. B. M. Depends on individual features The body, age, respancies, as well as from the quality and number of other non-protein components of food (carbohydrates, fats, vitamins, etc.). The amount of protein necessary for a person or an animal changes due to the biological value of food proteins, which is determined by the content of various amino acids in them (see amino acids). Many proteins and protein mixtures are defective due to the lack of certain amino acids in them, which cannot be synthesized in the human and animal organism. To compile food rations, focus on protein optimum, i.e., the amount of protein required to fully ensure the needs of the body; For an adult, it is equal, on average, 80-100 g. Protein, with severe physical work - 150 g. See proteins, protein exchange, metabolism. G. N. Kassil.
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
Watch what is a "protein minimum" in other dictionaries:
Protein minimum - - the minimum amount of protein, which is able to support nitrogenous equilibrium in the body; Determine by 1 kg of animal living mass: a horse at a closet of 0.7 0.8, a horse with 1.2 1.42; non-activating cow 0.6 0.7; lactating cow 1.0; sheeps,… … Dictionary of terms in physiology of farm animals
Protein exchange - protein exchange, concept covering the advent of protein substances in the body, their changes in the body (see the intermediate metabolism) and the allocation of protein combustion products in the form of urea, carbon dioxide, water and other chemical. connections. B. Exchange ... ...
The condition of the animal organism, in which the amount of nitrogen deposited (with urine and fender) is equal to the amount of nitrogen obtained with food. The adult organism is normal in the state of A. R. The average need for an adult in nitrogen 16 ... ...
- (from from ... and Greek. Dýnamis power, ability) isolation law, the possibility of replacing in the diet of some food substances Other in equivalent in energy ratios. The concept of I. was introduced by the German physiologist M. Rubner ... ... Great Soviet Encyclopedia
Protein substances, proteins, complex organic compounds that constitute the most important part of the protoplasm of each living cell. B. consist of carbon (50 55%), hydrogen (6.5 7.5%), nitrogen (15 19%), oxygen (20.0 23.5%), sulfur (0.3 2.5%) and sometimes… … Agricultural Dictionary - Directory
HOLIDAY HOUSE - Holiday home, an institution, aimed at providing workers and employees to restore its strength and energy in the most favorable and healthy conditions during the annual holidays received by them. Unlike the sanatorium D. about. Do not put ... ... Big medical encyclopedia
OBLITERATION - (Lat. Obliteratio Destruction), the term used to designate the closure, destruction of a cavity or a lumen by the growth of the tissue coming from the walls of this extensive education. The specified growth is more often ... ... Big medical encyclopedia
TUBERCULOSIS - Honey. Tuberculosis infectioncaused by Miko bacteria tuberculosis and characterized by the development of cell allergies, specific granules in various organs and tissues and a polymorphic clinical picture. Characterized by lung lesions ... Handbook of Diseases
Infectious diseases - Infectious diseases. In the representation of the Romans, the word "infectio" concluded the concept of a group of acute diseases, accompanied by fever, which often acquired the cooking distribution and dependent on the contamination of the air ... ... Big medical encyclopedia
FOOD - FOOD. Content: I. Nutrition like social. Hygienic problem. About Yayma P. In the light of the historical twee and Tin of human society ....... . 38 Problem P. in Capitalist Society 42 Production of P. products in Tsarist Russia and in the USSR ... Big medical encyclopedia
Physiological minimum protein
1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First health care. - M.: Large Russian Encyclopedia. 1994 3. encyclopedic Dictionary Medical terms. - M.: Soviet Encyclopedia. - 1982-1984.
Watch what is "physiological minimum protein" in other dictionaries:
See nitrogenous minimum ... Great Medical Dictionary
Great Medical Dictionary
- (Sin. Physiological minimum protein) The smallest amount of protein introduced with food, in which a nitrogenous equilibrium is preserved ... Medical encyclopedia
OBLITERATION - (Lat. Obliteratio Destruction), the term used to designate the closure, destruction of a cavity or a lumen by the growth of the tissue coming from the walls of this extensive education. The specified growth is more often ... ...
General view of the tree in the old Botanical garden of the city of Marburg (... Wikipedia
This term has other meanings, see aging. Old woman. Ann Pudder on April 8, 1917 in his 110nd birthday. Clear and dry skin Typical sign of aging person ... Wikipedia
This term has other meanings, see aging. The aging of man as aging of other organisms is the biological process of gradual degradation of parts and human body systems and the consequences of this process. Whereas ... ... Wikipedia
MENINGITIS - - inflammation of the shells of the head and spinal cord, as a rule, infectious genesis. Meningitis is classified according to etiologia (bacterial, viral, fungal, etc.), the nature of the inflammatory process (purulent, serous), the flow (sharp, ... ... Encyclopedic Dictionary of Psychology and Pedagogy
Roda - childbirth. Content: I. Definition of concept. Changes in the body during R. causes of the onset of p ..................... 109 II. The clinical course of physiological R. 132 Sh. Mechanics R. ................. 152 IV. Keeping p .................. 169 V ... Big medical encyclopedia
This article should be vico. Please refer it according to the rules of articles. Scattered sclerosis ... Wikipedia
Azoty Balance nitrogen equilibrium.
The remaining amino acids are easily synthesized in cells and are called replaceable. These include glycine, asparagic acid, asparagin, glutamic acid, glutamine, series, proline, alanine.
However, shywell food ends with the death of the body. The elimination of even one indispensable amino acid from the diet leads to the incomplete absorption of other amino acids and is accompanied by the development of negative nitrogen balance, exhaustion, stopping growth and impairment of the nervous system functions.
With a shit-blind diet, 4gr nitrogen is distinguished per day, which is 25GR protein (coefficient wear).
Physiological protein minimum is the minimum amount of proteins in food necessary to maintain a nitrogen equilibrium - 30-50 g / day.
Digestion of proteins in the gastrointestinal tract. Characteristics of peptidase of the stomach, the formation and role of hydrochloric acid.
In food products, the content of free amino acids is very small. The overwhelming amount is included in the composition of proteins that are hydrolyzed in the gastrointestinal tract under the action of protease enzymes). The substrate specificity of these enzymes is that each of them, with the highest speed, whipping peptide bonds formed by certain amino acids. Proteases, hydrolyzing peptide bonds inside the protein molecule, are attributed to the Endopeptidase group. Enzymes belonging to the exopeptidase group hydrolyze the peptide bond formed by end amino acids. Under the influence of all proteases, food seats are disintegrated into individual amino acids, which then come into tissue cells.
The formation and role of hydrochloric acid
The main digestive function of the stomach lies in the fact that the protein digestion begins in it. An essential role in this process plays hydrochloric acid. Proteins entering the stomach stimulate the selection histamine and groups of protein hormones - gastrin , which, in turn, cause secretion of NSI and Propriment - pepsinogen. NSI is formed in the shepherd cells of gastric glasses
The source of H + is H 2 C 3, which is formed in the stomach of the stomach from CO 2, diffusing from the blood, and H 2 o under the action of carboanhydrase enzyme
The dissociation H 2 CO 3 leads to the formation of a bicarbonate, which involving special proteins is highlighted in the plasma. Ions C1 - come into the lumen of the stomach through the chloride canal.
the pH is reduced to 1.0-2.0.
Under the action of NCLs, denaturation of food proteins that are not subjected to heat treatment, which increases the availability of peptide bonds for proteases. NCl has a bactericidal effect and prevents pathogenic bacteria to the intestines. In addition, hydrochloric acid activates pepsinogen and creates the optimum pH for the action of pepsin.
Pepsinogen - protein consisting of one polypeptide chain. Under the action of HCl, it turns into active pepsin in the process of activation as a result of partial proteolysis from the N-end of the pepsinogen molecule, the amino acid residues, which contain almost all positively charged amino acids available in pepsinogen are cleaved. Thus, negatively charged amino acids that participate in the conformational restructuring of the molecule and the formation of the active center are predominant in active pepsin. The active pepsine molecules formed under the action of HCl quickly activate the remaining pepsine molecules (autocatalysis). Pepsin primarily hydrolyzing peptide bonds in proteins formed by aromatic amino acids (phenylalanine, tryptophan, tyrosine) pepsin - endopeptidase, therefore, as a result of its action, shorter peptides are formed in the stomach, but not free amino acids.
In children breast-age In the stomach is an enzyme rennine (Himosin), causing milk coating. In the stomach of adults of Rennin people, there are no milk under the action of HCL and pepsin.
another protease - gastricin. All 3 enzymes (pepsin, renine and gastroin) are similar to the primary structure
Ketogenic and glycogenic amino acids. Anaplerotic reactions, synthesis of replaceable amino acids (example).
Catabolism Amino-T comes down to education piruvat, Acetyl-Coa, α -Chopoglutarate, Succinyl-CoA, Fumarate, oxaloacetate glycogenic amino acids - TRPs are converted into porvat and intermediate products and form ultimate oxaloacetate, glukegenesis origination can be used.
ketogenicamino-you in the process of catabolism are converted to acetoacetate (Liz, Lei) or acetyl-coolas and can be used in the synthesis of ketone bodies.
glycochetogenic The amino acids are used for the synthesis of glucose, and for the synthesis of ketone bodies, since in the process of their catabolism 2 products are formed - a certain metabolite of the citrate cycle and acetoacetate (three, hairdryer, tire) or acetyl-koa (ile).
Anaplerotic reactions - blessing residues of amino acids are used to replenish the amount of metabolites of the common catabolism, which is spent on the synthesis of biologically active substances.
The firth enzyme (coenzyme - biotin), catalyzing this reaction, is detected in the liver and muscles.
2. Amino acids → Glutamate → α-ketoglutarat
under the action of glutamatedehydrogenase or aminotransferase.
3. 
Propionyl-CoA, and then succinyl-CoA can also form when the decay of higher fatty acids with an odd number of carbon atoms
4. Amino acids → Fumarat
5. Amino acids → Oxaloacetate
Reactions 2, 3 occur in all tissues (except liver and muscles), where there is no piruvatakarboxylase.
VII. Byosynthesis of replaceable amino acids
In the human body, the synthesis of eight replaceable amino acids is possible: Ala, ASP, ASN, Ser, Gly, Depth, Pln, Pro. The carbon skeleton of these amino acids is formed from glucose. The α-amino group is introduced into the corresponding α-ketocislotes as a result of transamination reactions. Universal donor α -amino group serves glutamate.
By transamination of α-ketok acids formed from glucose, amino acids are synthesized
Glutamate It is also formed during the reducing amination α-ketoglutarata of glutamatedehydrogenase.
Transministration: Process scheme, enzymes, biorol. Alosa Biorol and AsaT and the clinical significance of their blood serum.
Transamination - the reaction of the transfer of α-amino group from ac-α to α-ketokislot, resulting in a new ketok acid and a new AK. The transamination process is easy to turn
The reactions catalyze aminotransferase enzymes, which serves pyridoxal phosphate (PF)
Aminotransferase found both in the cytoplasm and in the mitochondria of eukarot cells. In human cells, more than 10 aminotransferase were found, differing in substrate specificity. Almost all amino acids can enter into the transministration reaction with the exception of lysine, threonine and proline.
- In the first stage to pyridoxalphosphate, an amino group from the first substrate is attached to pyridoxalphosphate in the active center of the enzyme. The complex of enzyme-pyridoxes-min phosphate and ketokislo is formed - the first product of the reaction. This process includes an intermediate formation of 2 sheffed bases.
- In the second stage, the Pyridoxamine phosphate enzyme complex is connected to the ketokislot and through the intermediate formation 2 of the sheffed bases transmits an amino group to ketokislot. As a result, the enzyme returns to its native form, and a new amino acid is formed - the second product of the reaction. If the aldehyde group of pyridoxalphosphate is not occupied by the amino group of the substrate, it forms a Schiffovo base with a ε-amino group of lysine radical in the active center of the enzyme
Most often, amino acids are involved in transamination reactions, the content of which in the tissues are significantly higher than the rest - glutamate, alanine, aspartateand the corresponding ketocislotes - α -Chobrutarate, pyruvat and oxaloacetate.The main donor amino group is glutamate.
The most common enzymes in most mammalian tissues are: Alt (Alat) catalyzes the translucent reaction between the alanine and the α-ketoglutarata. This enzyme is localized in cytosol cells of many organs, but its largest amount is detected in liver cells and cardiac muscles. ACT (ASAT) catalyzes the reaction of trance-strain between the house and α-ketoglutarata. Oxaloacetate and glutamate are formed. Its most of its number is detected in the cells of the heart muscle and liver. Organship specificity of these enzymes.
Normally in the blood, the activity of these enzymes is 5-40 E / l. In case of damage to the cells of the corresponding organ, enzymes go into blood, where the activity is sharply rising. Since Act and Alt are most active in liver cells, hearts and skeletal muscles, they are used to diagnose diseases of these organs. In the cells of the heart muscle, the amount of ACT significantly exceeds the number of Alt, and in the liver - on the contrary. Therefore, especially informatively simultaneous measurement of the activity of both serum enzymes. Act / Alt Activities Relationship "Coefficient de Rightis".Normally, this coefficient is 1.33 ± 0.42. With myocardial infarction, ACT activity in the blood increases 8-10 times, and Alt - 2.0 times.
In hepatitis, the activity of Alt in the blood serum increases in ~8-10 times, and A ACT is 2-4 times.
Synthesis melaninov.
Types of melaninov
Reaction Activation of methionine
The active form of methionine is S-adenosylmethionine (SAM) is a sulfonial form of amino acids resulting from the addition of methionine to the adenosine molecule. Adenosine is formed during ATP hydrolysis.
This reaction catalyzes the enzyme methionine adenosyltransferase, which is present in all types of cells. The structure (-s + -ch 3) in SAM is an unstable group that determines the high activity of the methyl group (hence the term "active methionine"). This reaction is unique for biological systems, since, apparently, is the only known reaction, as a result of which all three phosphate residues of ATP are released. The cleavage of the methyl group from SAM and transfer it to the compactor connection catalyze methyltransferase enzymes. SAM during the reaction turns into S-adenosylgomocysteine \u200b\u200b(SAT).
Synthesis Creatine
Creatine is necessary for education in the muscles of the high-energy compound - credit-atin phosphate. Creatine synthesis goes in 2 stages with the participation of 3 amino acids: arginine, glycine and methionine. In kidneys Guaninitzetat is formed under the action of glycinamadinotransferase. Then guanidine acetate is transported in the liver where its methylation is reacting.
TransMetrization reactions are also used for:
- synthesis of adrenaline from norepinephrine;
- anzherin synthesis from carnosine;
- methylation of nitrogen bases in nucleotides, etc.;
- inactivation of metabolites (hormones, mediators, etc.) and disposal of alien compounds, including drugs.
Inactivation of biogenic amines also occurs:
methylation with the participation of SAM under the action of methyltransferase. Thus, various biogenic amines can be inactivated, but the inactivation of gastamine and adrenaline occurs most often. Thus, the inactivation of adrenaline occurs through the methylation of the hydroxyl group in the orthosuit
Ammonia toxicity. His education and neutralization.
Catabolism of amino acids in the tissues occurs constantly at the rate of ~100 g / day. At the same time, a large amount of ammonia is exempt as a result of deamination of amino acids. Significantly smaller amounts are formed during the deamination of biogenic amines and nucleotides. Part of the ammonia is formed in the intestine as a result of the action of bacteria on food proteins (rotting proteins in the intestine) and enters the blood of the carrier vein. The concentration of ammonia in the blood of the carrier vein is significantly larger than in general blood flow. A large amount of ammonia is delayed in the liver, which maintains a low content of it in the blood. The concentration of ammonia in the blood is rather rarely exceeds 0.4-0.7 mg / l (or 25-40 μmol / l
Ammonia - toxic connection. Even a small increase in its concentration has an adverse effect on the body, and above all on the CNS. So, an increase in ammonia concentration in the brain to 0.6 mmol causes convulsions. Hyperammonimia symptoms include tremor, inseparable speech, nausea, vomiting, dizziness, convulsive seizures, loss of consciousness. In severe cases, a coma with fatal outcome is developing. The mechanism of toxic ammonia to the brain and the body as a whole is obviously associated with the action of it into several functional systems.
- Ammonia easily penetrates membranes into cells and in mitochondriah shifts the reaction catalyzed by glutamate dehydrogenase, towards the formation of the depth:
α-ketoglutarate + nadh + n + + nh 3 → glutamate + nad +.
The decrease in the concentration of α-ketoglutaratus causes:
· Infection of the exchange of amino acids (trans-mining reaction) and, therefore, the synthesis of them of neurotransmitters (acetylcholine, dopamine, etc.);
· Gypoenergetic state as a result of a reduction in the CTC speed.
The insufficiency of the α-ketoglutarata leads to a decrease in the concentration of CTC metabolites, which causes the acceleration of the reaction of the synthesis of oxalua-cetatat from the pyruvate, accompanied by intensive consumption of CO 2. Enhanced formation and consumption of carbon dioxide with hyperamonmoniums are particularly characteristic of brain cells. Increasing the concentration of ammonia in the blood shifts the pH into the alkaline side (causes alkalosis). This, in turn, increases the affinity of hemoglobin to oxygen, which leads to the hypoxia of tissues, accumulating CO 2 and hypoenergetic state, which mainly suffers from the headmage. High ammonia concentrations stimulate glutamine synthesis from glutamate in nervous tissue (with the participation of glutaminescentatase):
Glutamate + NH 3 + ATP → Glutamine + ADF + H 3 P0 4.
· The accumulation of glutamine in neuroglia cells leads to an increase in osmotic pressure in them, the swelling of astrocytes and in large concentrations can cause the brain edema. The concentration of glutamate disrupts the exchange of amino acids and neurotransmitters, in particular the synthesis of U-aminobacing acid (GABA), the main brake mediator. With a lack of gamke and other mediators, the nervous impulse is disturbed, convulsions arise. NH 4 + ion almost does not penetrate the cytoplasmic and mitochondrial membranes. The excess of ammonium ion in the blood is able to violate the transmembrane transfer of monovalent Na + and K + cations, competing with them for ion channels, which also affects nerve impulses.
The high intensity of the processes of deamination of amino acids in the tissues and the very low level of ammonia in the blood indicate that the cells are actively binding to ammonia with the formation of non-toxic compounds, which are derived from the body with urine. These reactions can be considered an ammonia neutralization reactions. Several types of such reactions were found in different tissues and organs. The main reaction of the binding of ammonia flowing in all tissues of the body is 1.) Synthesis of glutamine under the action of glutamine synthetase:
The glutaminesyntetase is localized in cell mitochondria, a cofactor - ions Mg 2+ are required for the enzyme work. Glothumnsintetase - one of the main regulatory enzymes of the exchange of amino acids and is altogether is inhibited by AMP, glucose-6-phosphate, as well as Gly, Ala and GIS.
In intestinal cells Under the action of the enzyme of glutaminase occurs the hydrolytic release of amid nitrogen in the form of ammonia:
The glutamate formed in the reaction is subjected to transamination with pyruvat. Os-amino glutamic acid is transferred to Alanine:
Glutamine is the main nitrogen donor in the body. The amide nitrogen of glutamine is used to synthesize purine and pyrimidine nucleotides, asparagine, aminosahares and other compounds.
METHOD OF POL-B Urea definition in serum
In biological fluids, M. is determined by means of gasometric methods, direct photometric methods based on the reaction of M. with various substances With the formation of equimolecular quantities of painted products, as well as enzymatic methods using mainly ureaz enzyme. The gasometric methods are based on the oxidation of M. sodium hyperobrom in an alkaline medium NH 2 -CO-NH 2 + 3NABRO → N 2 + CO 2 + 3NABRO + 2H 2 O. The volume of gaseous nitrogen is measured using a special apparatus, most often of the Borodin apparatus. However, this method has low specificity and accuracy. From the photometric most common methods based on the reaction of M. with diacetylmonoxim (Faron reaction).
To determine the urea in serum and urine, a unified method is used based on the reaction of M. with diacetylmonoxime in the presence of thiosemicarbazid and iron salts in an acidic environment. Another unified method of determining M. is a Urease method: NH 2 -CO-NH 2 → Ureaz NH 3 + CO 2. Allocated ammonia forms sodium hypochloride and phenol indofenol having blue colour. The intensity of the color is proportional to the content of M. in the test sample. Ureaznaya reaction highly specific, for research takes only 20 μl Serum diluted in a ratio of 1: 9 with NACI solution (0.154 m). Sometimes instead of phenol use sodium salicylate; Serum is bred as follows: to 10 μl Serums are added 0.1 mlwater or NACI (0.154 m). The enzymatic reaction in both cases occurs at 37 ° for 15 and 3-3 1/2 min.respectively.
Derivatives M., in the molecule of which hydrogen atoms are substituted with acid radicals, are called ureyids. Many Ureids and some of their halogen-substituted derivatives in medicine are used as medicines. Ureidams include, for example, barbituric acid salts (Mulonylovians), Alloxan (Mesoksalylmoevina); The heterocyclic ureide is urinary acid .
The overall diagram of the heme decay. "Direct" and "indirect" bilirubin, the clinical significance of its definition.
Gem (hemoxygenase) -biliverdin (biliverdinreductase) -bilirubin (UDF glucuranylTransferase) -bitrubinmoglyucronid (ud-glucuronyltransferase) -birubidiglucronid
In normal condition, the concentration of the total bilirubin in the plasma is 0.3-1 mg / dl (1.7-17 μmol / l), 75% of the total bilirubin is in non-conjugated form (indirect bilirubin). In the clinic, the conjuncture bilirubin is called direct, because it is water soluble and can quickly interact with the diazore agent, forming a pink connection - this is a direct reaction van der Berg. Unconjugated bilirubin hydrophobine, therefore, in the blood plasma, it is contained in a complex with albumin and does not react with the diazoreactive until an organic solvent is added, for example ethanol, which precipitates albumin. Unconjugated or clinged, interacting with the azocracy only after the deposition of the protein, is called indirect bilirubin.
In patients with liver cell pathology, accompanied by a long-term increase in the concentration of conjugated bilirubin, the third shape of a plasma bilirubin is detected in the blood, in which bilirubin is covalently associated with albumin, and therefore it is impossible to separate it in the usual way. In some cases, up to 90% of the total content of bilirubin of blood may be in this form.
Methods for detecting hemoglobin: physical (spectral analysis of hemoglobin and its derivatives); Physico-chemical (obtaining crystals of hydrogen hemin).
Spectral analysis of hemoglobin and its derivatives. The use of spectrographic methods When considering the solution of oxygemoglobin, reveals in the yellow-green part of the spectrum between the phraungafer lines D and E two system absorption bands, in the restored hemoglobin in the same part of the spectrum there is only one wide band. The differences in the absorption of radiation hemoglobin and oxymemoglobin served as the basis for the method of studying the degree of blood saturation with oxygen - oxygemometry.
Karbgemoglobin in its spectrum is close to oxymemoglobin, however, when the restorative substance is added, two absorption bands appear in carbgemoglobin. The methemoglobin spectrum is characterized by one narrow absorption band on the left at the border of the red and yellow part of the spectrum, the second narrow strip on the border of yellow and green zones, finally, the third wide band in the green part of the spectrum
Ghememin or salty hemo-tina crystals. From the surface of the spots, it scraps onto the slide and crushes several grains. They are added 1-2 grains of cooking salts and 2-3 drops of icy cinema to-you. Everyone is covered with coating glass and carefully, without bringing to a boil, heated. The presence of blood is proved by the appearance of brown-yellow microcrystals in the form of rhombic tablets. If the crystals are poorly formed, then have a kind of cannabis seed. The preparation of hemin crystals certainly proves the presence in the test blood object. Negative sample result does not matter. Fat, rust makes it difficult to obtain hemin crystals
Active oxygen forms: anion superoxide, hydrogen peroxide, hydroxyl radical, peroxynitrite. Their formation, causes of toxicity. The physiological role of AFC.
In the CPE, about 90% of the cell arriving in cells is absorbed. The rest of 2 is used in other OSR. The enzymes involved with OSR using O2 are divided into 2 groups: oxidases and oxygenases.
Oxidases use molecular oxygen only as an electron acceptor, restoring it to H 2 O or H 2 O 2.
Oxygenase include one (monooxygenase) or two (dioxigenases) of an oxygen atom into the resulting reaction product.
Although these reactions are not accompanied by synthesis ATF.They are necessary for many specific reactions in the exchange of amino acids), synthesis of greyety acids and steroids), in the reactions of neutralization of foreign substances in the liver
In most reactions involving molecular oxygen, its recovery occurs phased with the transfer of one electron at each stage. With one-electron transfer, the formation of intermediate high-formative oxygen forms is the formation.
In an unexcited state, oxygen is non-toxic. The formation of toxic forms of oxygen is associated with the peculiarities of its molecular structure. O 2 contains 2 unpaired electron, which are located on different orbital. Each of these orbital can take another electron.
Complete recovery of 2 occurs as a result of 4 single-electronic transitions:
Superoxide, peroxide and hydroxyl radical - active oxidizers, which represents a serious danger to many block components of the cell
Active forms of oxygen can eliminate electrons from many compounds, turning them into new free radicals, initiating chain oxidative reactions
The damaging effect of free radicals on cell components. 1 - protein destruction; 2 - ER damage; 3 - the destruction of the nuclear membrane and DNA damage; 4 - the destruction of mitochondrial membranes; Penetration into the cell of water and ions.
The formation of superoxide in the CPE. The leakage of electrons in the CPE can occur when transferring electrons with the participation of Coenzyme Q. When restoring the Ubiquinone turns into an anion-radical of the sevenhinone. This radical does not interact with O 2 with the formation of a superoxide radical. 
Most of the active forms of oxygen are formed when the electrons are transferred to the CPE, primarily when the QH 2-dehydrogenase complex is functioning. This occurs as a result of non-enzymatic transfer ("leakage") of electrons with QH 2 per oxygen (
at the electron transfer phase, with the participation of cytochromucleonide (complex IV), the leakage of electrons does not occur due to the presence of special active centers containing Fe and Cu in the enzyme and restoring O 2 without release of intermediate free radicals.
In phagocytic leukocytes, the absorption of oxygen and the formation of active radicals increase in phagocytosis. The active forms of oxygen are formed as a result of activation of NADPH-oxidase, preferably localized on the outside of the plasma membrane, initiating the so-called "respiratory explosion" to form an active forms of oxygen
The protection of the organism on the toxic effect of the active forms of oxygen is associated with the presence of highly specific enzymes in all cells: superoxiddismutase, catalase, glutathione-peroxidase, as well as with the action of antioxidants.
Dehydration of active oxygen forms. Enzyme antioxidant system (catalase, superoxiddismutase, glutathioneer-peroxidase, glutathionereductase). Process schemes, biorol, place of leakage.
Superoxiddismutase catalyzes the response of the dysmutation of superoxide anion - radicals:
O2.- + O2.- \u003d O2 + N 2O2
During the reaction, hydrogen peroxide was formed, it is capable of inactivating soda, so superoxiddismutaza Always "works" in a pair of a scatlase, which quickly and effectively splits hydrogen peroxide into absolutely neutral connections.
Catalase (CF 1.11.1.6) - Hematoprotein, which catalyzes the reaction of the detection of hydrogen peroxide formed by the reaction of the superoxide radical dismutation:
2H2O2 \u003d 2H2O + O2
Glutathioneperoxidazakes the reactions in which the enzyme restores hydrogen peroxide to water, as well as the restoration of organic hydroperoxides (ROOH) to hydroxy derivatives, and as a result, goes into the oxidized disulfide form GS-SG:
2GSH + H2O2 \u003d GS-SG + H2O
2GSH + ROOH \u003d GS-SG + ROH + H2O
Glutathione peroxidase It neutralizes not only H2O2, but also different organic lipid peroxyls that are formed in the body when the floor is activated.
GlutathionedUctaza (KF 1.8.1.7) - Flavoprotein with a prosthetic group of flavineenindinucleotide, consists of two identical subunits. GlutathionedUctaza Catalyzes the reaction of the reduction of glutathione from its oxidized GS-SG form, and all other glutathionic enzymes use it:
2Nadph + GS-SG \u003d 2NADP + 2 GSH
This is a classic cytosol enzyme of all eukaryotes. Gulutationtransferase catalyzes the reaction:
RX + GSH \u003d HX + GS-SG
Phase of conjugation in the system of neutralization of toxic substances. Types of conjugation (examples of reactions with FAFS, UDFGK)
Conjugation - the second phase of the neutralization of substances during which it takes to the functional groups forming at the first stage, other molecules or groups of endogenous origin, increasing hydrophilicity and reduce xenobiotic toxicity
1. Participation of transfer in conjugation reactions
UDF glucuronelTransferase. Localized in uridin-diphosphate (UDF) -HurdinylTransferase (UDF) - glucuronicransferase join the residue of glucuronic acid to the molecule of the substance formed during the microeal oxidation
In general form: ROH + UDF-C6H9O6 \u003d RO-C6H9O6 + UDF.
Sulfotransferase. Cytoplasmic Calpotransferase catalyzed the conjugation reaction, during which the residue of sulfuric acid (-SO3H) from 3 "phosphoadenosine-5" -phosphosulfate (FAFS) is attached to phenol, alcohols or amino acids.
Reaction in general form: ROH + FAF-SO3H \u003d RO-SO3H + FAF.
Sulfotransferase enzymes and UDF glucuronyltransferase are involved in the neutralization of xenobiotics, inactivating drugs and endogenous biologically active compounds.
Glutathionisferase. A special place among the enzymes involved in the neutralization of xenobiotics, the inactivation of normal metabolites, drugs, occupy glutathioneransferase (GT). GlutathyonTransferase function in all tissues and play an important role in the inactivation of their own metabolites: some steroid hormones, bilirubin, gully acids, in the GT cell are mainly localized in cytosole, but there are variants of enzymes in the nucleus and mitochondria.
The glutathione is a tripeptide of de-cis-gel (the residue of glutamic acid is attached to the cis-chain by the carboxyl group of the radical). GT has a wide specificity of substrates, the total number of which exceeds 3000. GT is associated with very many hydrophobic substances and inactivate them, but only those that have a polar group are subject to the chemical modification with gluration. That is, the substrates serve substances that, on the one hand, have an electrophilic center (for example, a group), and on the other hand, hydrophobic zones. Neutralization, i.e. Chemical modification of xenobiotics with the participation of GT, can be carried out in three different ways:
by conjugation of the substrate R with glutathione (GSH): R + GSH → GSRH,
as a result of nucleophilic substitution: Rx + GSH → GSR + NX,
recovery of organic peroxides to alcohols: R-HC-O-OH + 2 GSH → R-HC-OH + GSSG + H2O
In the reaction: UN is a hydroperoxide group, GSSG - oxidized glutathione.
Sishem neutralization involving GT and glutathione plays a unique role in the formation of the organism resistance to the most different effects and is the most important protective mechanism of the cell. During the biotransformation of some xenobiotics under the action of GT, thioethers are formed (RSG conjugates), which are then converted to mercaptanes, among which toxic products are detected. But GSH conjugates with most xenobiotics are less reactive and more hydrophilic, than starting materials, and therefore less toxic and easier are removed from the body
GT with its hydrophobic centers can be non-covalently binding a huge amount of levels of levels (physical neutralization), preventing their introduction to the lipid layer of membranes and disruption of cell functions. Therefore, GT is sometimes called intracellular albumin.
GT can covalently bind xenobiotics, which are strong electrolytes. The attachment of such substances is "suicide" for GT, but an additional protective mechanism for the cell.
Acetyltransferase, methyltransferase
Acetyltransferase catalyze the reactions of conjugation - the transfer of acetyl residue from acetyl-economy on the nitrogen group -SO2NH2, for example as part of sulfanimamides. Membrane and cytoplasmic methyltransferase with SAM participation methylate groups -R \u003d O, -NH2 and SH-group xenobiotics.
The role of epoxydhydrolaz in the formation of diols
In the second phase of neutralization (reactions of conjugation), some other enzymes take part. Epoxydhydrolaise (epoxydratosis) joins water to benzene epoxides, benzpyrin and other polycyclic hydrocarbons formed during the first phase of neutralization, and turns them into diols (Fig. 12-8). Epoxy formed during microsomal oxidation are carcinogens. They have high chemical activity and can participate in the reactions of non-enzyme alkylation of DNA, RNA, proteins. Chemical modifications of these molecules can lead to the reincarnation of the normal cell into the tumor.
The role of proteins in nutrition, norms, nitrogen balance, wear coefficient, physiological protein minimum. Protein deficiency.
AK contain almost 95% of the total nitrogen, therefore they are supporting the nitrate balance of the body. Azoty Balance - The difference between the amount of nitrogen coming from food, and the amount of nitrogen allocated. If the amount of nitrogen incoming nitrogen is the number of allocated, then comes nitrogen equilibrium. This condition is a healthy person with normal nutrition. A nitrogen balance can be positive (nitrogen goes more than derived) in children, in patients. A negative nitrogen balance (nitrogen release prevails over its intake) is observed when aging, starvation and during heavy diseases. With a protein diet, a nitrate balance becomes negative. The minimum number of proteins in the feed needed to maintain a nitrogen equilibrium corresponds to 30-50 g / CYT, the optimal amount with an average physical activity is ~100-120 g / day.
amino acids whose synthesis is complicated and uneconomic for the body is obviously more profitable to receive with food. Such amino acids are called indispensable. These include phenylalanine, methionine, threonine, tryptophan, valine, lysine, leucine, isoleucine.
Two amino acids - arginine and histidine called partially replaceable. - Tyrosine and cysteine \u200b\u200bare conventionally replaced, as an indispensable amino acids are needed for their synthesis. Tyrosine is synthesized from phenylalanine, and for the formation of cysteine, a methionine sulfur atom needs.
The remaining amino acids are easily synthesized in cells and are called replaceable. These include glycine, aspartic acid, asparagin, glutamic acid, glutamine, series,
