History of enzymes chemistry presentation. Presentation - enzymes. Where does our body get enzymes?
Enzymes Enzymes are biological catalysts of a protein nature that accelerate chemical reactions in living organisms and outside them. J. Sumner was the first to obtain the enzyme urease in its pure form and proved that the action of enzymes is not associated with the cell. In addition to him, both domestic (K.S. Kirchhoff, I.P. Pavlov, S.E. Severin, V.A. Engelgard, etc.) and foreign scientists made significant contributions to enzymology, or enzymology, the study of enzymes (E. Fisher, J. Nortron, A. Spalanzini, M. Duclos, etc.).
Structure of enzymes single-component, two-component enzymes (simple proteins) (protein + active group) active group coenzyme prosthetic group (determines catalytic activity, protein part)
ENZYMES (according to the type of reaction catalyzed) Oxidoreductases are redox enzymes. Transferases are transfer enzymes. They transport individual groups, radicals and atoms, both between individual molecules and within them. Hydrolases are enzymes that accelerate hydrolysis reactions, i.e. the process of breaking down complex substances into simpler ones with the addition of water molecules. Lyases are enzymes that hydrolytically cleave various groups from substrates. Isomerases are enzymes that accelerate the isomerization of organic compounds (intramolecular rearrangements). Ligases are enzymes that accelerate the synthesis of complex compounds from simpler ones due to the breakdown of pyrophosphate bonds (ATP).
Properties of enzymes Selectivity (selectivity of their action) Determined by the ability of an enzyme to convert only a given type of substrate in certain reactions and conditions.
High catalytic activity The addition of a small concentration of enzyme accelerates the conversion of the substrate by 10 8 - 10 12 times. Stability Ability to maintain catalytic activity Specificity
Temperature Dependence Many enzymes are most effective at human body temperature, i.e. approximately at A person dies at lower and higher temperatures not so much because the disease killed him, but so much because the enzymes stop functioning, and therefore the metabolic processes that determine the existence of the organism stop. Dependence on pH of the environment Enzymes act most effectively on the substrate under a strictly defined solution environment.
pH values of physiological fluids Medium pH value Possible deviations Gastric juice 1.7 0.9-2.0 Hepatic bile 7.4 6.2-8.5 Cystic bile 6.8 5.6-8.0 Blood (plasma) 7 .4 7.25-7.44 Urine 5.8 5.0-6.5 Sweat 7.4 4.2-7.8 Tear fluid 7.7 7.6-7.8 Saliva 6.8 5.6 -7.9 Cerebrospinal fluid 7.6 7.4-7.8 Upper colon juice 6.1 - Pancreatic juice 8.8 8.6-9 Small intestine juice 6.5 5.1-7.1
Some examples of the use of enzymes in industry enzyme industry use of Amylase (break down starch) Brewing Saccharification of starch contained in malt Textile Removal of starch applied to threads during sizing Bakery Starch - glucose. Yeast cells, fermenting glucose, produce carbon dioxide, the bubbles of which loosen the dough and give the bread a porous structure. The bread browns better and does not go stale longer.
Proteases (break down proteins) Papain Brewing Stages of the brewing process that regulate the quality of beer Meat Softening of meat. This enzyme is quite resistant to temperature increases and continues to act for some time when meat is heated. Then, of course, it is inactivated. Ficin Pharmaceutical Additive to toothpastes to remove plaque. Photo Washing gelatin from used film in order to extract the silver contained in it. Pepsin Food Production of ready-made cereals. Pharmaceutical Drugs that aid digestion (in addition to the normal action of pepsin in the stomach)
Trypsin Food Production of baby food products Renin Cheese making Milk coagulation (producing a casein coagulum) Bacterial proteinases Washing clothes Washing powders with enzymatic additives Tanning Hair separation - a method in which neither hair nor skin is damaged Textile Extracting wool from scraps of sheep skins Food Protein production hydrolysates (in particular for feed production)
Glucose oxidase Food Removal of glucose or oxygen Catalase Food Removal of hydrogen peroxide Rubber Production (from hydrogen peroxide) of oxygen necessary to convert latex into spongy rubber Cellulose Food Clarification of fruit juices Pectinase
Thousands and thousands of enzymatic reactions occur in the human body every second. - The enzyme amylase, which is found in saliva and in the juice of the small intestine, helps convert starch into maltose. - Maltose is then converted to glucose in the small intestine by the enzyme maltase. - In the stomach and small intestine, enzymes such as pepsin and trepsin convert proteins into simpler compounds called peptides. - Peptides are dissolved in the small intestine to amino acids under the action of enzymes - peptidases. - Lipase enzyme acts on fats (lipids) in the small intestine, breaking them down into glycerol and fatty acids.
Questions and tasks 1. What are enzymes? 2. How does the action of enzymes differ from the action of inorganic catalysts? 3.List the factors that affect the rate of an enzymatic reaction. 4. At what temperature do enzymes exhibit the greatest activity: 26, 36, 56 C? 5.Indicate the optimal pH values for the action of amylase and pepsin. 6.How are enzymes classified and how are their trivial names formed? 7.Name the areas of application of enzymes in industry. 8. Citric acid is produced industrially by microbiological (enzymatic) fermentation of a sucrose solution according to the equation
How many kg of citric acid, with a yield of 62% of the theoretically possible, can be obtained from 520 kg of a 15% sucrose solution? 9. To produce lactic acid by microbiological (enzymatic) fermentation, industry uses starch and molasses. How many kilograms of lactic acid, with a yield of 75% of the theoretically possible, can be obtained from 640 kg of feed molasses, if the mass fraction of dry substances in it is 80%, of which sucrose accounts for 45%?
Slide 1
Slide 2
What are enzymes? FARMS (from the Latin “fermentum” - fermentation, leaven), enzymes, specific proteins that increase the rate of chemical reactions in the cells of all living organisms. They are also called biocatalysts by analogy with catalysts in chemistry. Each type of enzyme catalyzes the transformation of certain substances (substrates), sometimes only a single substance in a single direction. Therefore, numerous biochemical reactions in cells are carried out by a huge number of different enzymes.
Slide 3
History of the discovery of enzymes Processes occurring with the participation of enzymes have been known to man since ancient times, because the preparation of bread, cheese, wine and vinegar is based on enzymatic processes. But only in 1833, for the first time, an active substance was isolated from germinating barley grains, which converted starch into sugar and was called diastase (now this enzyme is called amylase). At the end of the 19th century. It has been proven that the juice obtained by grinding yeast cells contains a complex mixture of enzymes that ensure the process of alcoholic fermentation. From that time on, intensive study of enzymes began - their structure and mechanism of action.
Slide 4
The role of enzymes in the body Enzymes are involved in all metabolic processes and in the implementation of genetic information. The ability to quickly digest foods in a living organism is achieved thanks to them. Enzymes are the “workforce” that builds your body, just like builders build houses. You may have all the building materials you need, but to build a house you will need workers, which is what they are.
Slide 5
There are many enzymes that work in the body. Each of them has its own purpose. Protease is an enzyme that digests protein, lipase digests fats; amylase digests carbohydrates and cellulase digests fiber.
Slide 6
Where does our body get enzymes? We inherit a certain enzyme potential at birth. This limited supply lasts a lifetime. The faster you use up enzyme energy, the faster you will run out of energy. You live as long as your body has enzyme activity factors from which it produces new enzymes. When you reach a point where your body is no longer able to produce enzymes, your life is over. For humans, the main source of “extra” enzymes is food. It must contain a “certain set” of them. If enzymes are present in food, then they themselves carry out a significant part of the work of digesting food. But if you eat food that has been heat-processed and lacks enzymes, the body is forced to produce enzymes for digestion. This greatly reduces the limited enzyme potential.
Slide 7
Today we know that cancer cells are protected by a protein coat that prevents the immune system from recognizing them. Only enzymes can remove this membrane, thus exposing the malignant cells. That is why cancer patients limit meat in their diet or exclude it altogether: this saves the enzymes that go into breaking down meat, giving them the opportunity to participate in exposing cancer cells. So, if you eat something boiled, and always expose the meat to heat or other processing, then be sure to eat 3 times more raw vegetables along with the cooked product.
Slide 8
Enzymes constantly work in the body: without them, not a single process takes place. They break down food at the cellular level, create muscle from proteins, release carbon dioxide from the lungs, support the immune system in its fight against infection, increase the body's endurance level, and help the digestive system function properly. In addition to all of the above, enzymes: - destroy and remove various fats from the body; - prevent the chronic course of the disease; - keep us young and help us look good; - increase energy and endurance; - prevent hormonal imbalance in the body.
Slide 9
Catalytic properties of enzymes Enzymes are the most active among all known catalysts. Most reactions in the cell proceed millions and billions of times faster than if they occurred in the absence of enzymes. Thus, one molecule of the catalase enzyme is capable of converting up to 10 thousand molecules of hydrogen peroxide, toxic to cells, formed during the oxidation of various compounds, into water and oxygen in a second. The catalytic properties of enzymes are due to their ability to significantly reduce the activation energy of reacting compounds, that is, in the presence of enzymes, less energy is required to “start” a given reaction.
Slide 10
Conditions for the action of enzymes All reactions involving enzymes occur mainly in a neutral, slightly alkaline or slightly acidic environment. However, the maximum activity of each individual enzyme occurs at strictly defined pH values. For the action of most enzymes in warm-blooded animals, the most favorable temperature is 37-40oC.
Slide 11
In plants, at temperatures below 0o C, the action of enzymes does not completely stop, although the vital activity of plants is sharply reduced. Enzymatic processes, as a rule, cannot occur at temperatures above 70o C, since enzymes, like any proteins, are subject to thermal denaturation (structural destruction).
Slide 12
Chemical nature of enzymes All enzymes are proteins with a molecular weight from 15,000 to several million Da. All enzymes are proteins, but not all proteins are enzymes. Based on their chemical structure, they are divided into simple and complex (they have a non-protein part or a prosthetic group). The functions of the prosthetic group are as follows: participation in the act of catalysis, contact between the enzyme and the substrate, stabilization of the enzyme molecule in space.
Slide 13
In the process of catalyzing a reaction, not the entire enzyme molecule, but a certain part of it, which is called the active center, comes into contact with the substrate. This zone of the molecule does not consist of a sequence of amino acids, but is formed by twisting the protein molecule into a tertiary structure. Individual sections of amino acids come closer to each other, forming a specific configuration of the active center. In addition to the active center, a number of enzymes are equipped with a regulatory (allosteric) center. Substances that affect its catalytic activity interact with this zone of the enzyme.
Slide 14
Sizes of enzymes and their structure The molecular weight of enzymes, like all other proteins, lies in the range of 10 thousand - 1 million (but may be more). They may consist of one or more polypeptide chains and may be represented by complex proteins. The latter, along with the protein component (apoenzyme), includes low-molecular compounds - coenzymes (cofactors, coenzymes), including metal ions, nucleotides, vitamins and their derivatives. Some enzymes are formed in the form of inactive precursors (proenzymes) and become active after certain changes in the structure of the molecule, for example, after the cleavage of a small fragment from it. Many enzymes form so-called enzyme complexes. Such complexes, for example, are embedded in the membranes of cells or cellular organelles and are involved in the transport of substances. The cause of another hereditary disease - phenylketonuria, accompanied by a disorder of mental activity, is the loss of the ability of liver cells to synthesize the enzyme that catalyzes the conversion of the amino acid phenylalanine into tyrosine. Determination of the activity of many enzymes in blood, urine, cerebrospinal, seminal and other body fluids is used to diagnose a number of diseases. Using this blood serum analysis, it is possible to detect myocardial infarction, viral hepatitis, pancreatitis, nephritis and other diseases at an early stage. Slide 17
Use of enzymes by humans Since enzymes retain their properties outside the body, they are successfully used in various industries. For example, papaya proteolytic enzyme (from papaya juice) - in brewing, to soften meat; pepsin - in the production of “ready-made” cereals and as a medicinal product; trypsin - in the production of baby food products; rennin (rennet from the stomach of a calf) - in cheese making. Catalase is widely used in the food and rubber industries, and cellulases and pectidases that break down polysaccharides are used to clarify fruit juices.
Enzymes
Completed by: Mandzhieva Erkena
Student group DeB(bak)1-1
What are enzymes?
ENZYMES (from the Latin “fermentum” - fermentation, leaven), enzymes, specific proteins that increase the rate of chemical reactions in the cells of all living organisms. They are also called biocatalysts by analogy with catalysts in chemistry. Each type of enzyme catalyzes the transformation of certain substances (substrates), sometimes only a single substance in a single direction. Therefore, numerous biochemical reactions in cells are carried out by a huge number of different enzymes.
History of enzyme discovery
Processes that occur with the participation of enzymes have been known to man since ancient times, because the preparation of bread, cheese, wine and vinegar is based on enzymatic processes. But only in 1833, for the first time, an active substance was isolated from germinating barley grains, which converted starch into sugar and was called diastase (now this enzyme is called amylase). At the end of the 19th century. It has been proven that the juice obtained by grinding yeast cells contains a complex mixture of enzymes that ensure the process of alcoholic fermentation. From that time on, intensive study of enzymes began - their structure and mechanism of action.
The role of enzymes in the body
Enzymes are involved in all metabolic processes and in the implementation of genetic information. The ability to quickly digest foods in a living organism is achieved thanks to them.
Enzymes are the “workforce” that builds your body, just like builders build houses. You may have all the building materials you need, but to build a house you will need workers, which is what they are.
There are many enzymes that work in the body. Each of them has its own purpose. Protease is an enzyme that digests protein, lipase digests fats; amylase digests carbohydrates and cellulase digests fiber.
Where does our body get enzymes?
We inherit a certain enzyme potential at birth. This limited supply lasts a lifetime. The faster you use up enzyme energy, the faster you will run out of energy. You live as long as your body has enzyme activity factors from which it produces new enzymes. When you reach a point where your body is no longer able to produce enzymes, your life is over.
For humans, the main source of “extra” enzymes is food. It must contain a “certain set” of them. If enzymes are present in food, then they themselves carry out a significant part of the work of digesting food. But if you eat food that has been heat-processed and lacks enzymes, the body is forced to produce enzymes for digestion. This greatly reduces the limited enzyme potential.
Today we know that cancer cells are protected by a protein coat that prevents the immune system from recognizing them. Only enzymes can remove this membrane, thus exposing the malignant cells. This is why cancer patients limit meat in their diet or exclude it altogether: this saves the enzymes that go into breaking down meat, giving them the opportunity to participate in exposing cancer cells
So, if you eat something boiled, and the meat is always subjected to heat or other processing, then be sure to eat 3 times more raw vegetables along with the boiled product.
Enzymes constantly work in the body: without them, not a single process takes place. They break down food at the cellular level, create muscle from proteins, release carbon dioxide from the lungs, support the immune system in its fight against infection, increase the body's endurance level, and help the digestive system function properly. In addition to all of the above, enzymes:
- destroy and remove various fats from the body;
- prevent the chronic course of the disease;
- keep us young and help us look good;
- increase energy and endurance;
- prevent hormonal imbalance in the body.
Catalytic properties of enzymes
Enzymes are the most active of all known catalysts. Most reactions in the cell proceed millions and billions of times faster than if they occurred in the absence of enzymes. Thus, one molecule of the catalase enzyme is capable of converting up to 10 thousand molecules of hydrogen peroxide, toxic to cells, formed during the oxidation of various compounds, into water and oxygen in a second. The catalytic properties of enzymes are due to their ability to significantly reduce the activation energy of reacting compounds, that is, in the presence of enzymes, less energy is required to “start” a given reaction.
Slide No. 10
Enzyme action conditions
All reactions involving enzymes occur mainly in a neutral, slightly alkaline or slightly acidic environment. However, the maximum activity of each individual enzyme occurs at strictly defined pH values. For the action of most enzymes in warm-blooded animals, the most favorable temperature is 37-40oC.
Slide No. 11
In plants, at temperatures below 0o C, the action of enzymes does not completely stop, although the vital activity of plants is sharply reduced. Enzymatic processes, as a rule, cannot occur at temperatures above 70o C, since enzymes, like any proteins, are subject to thermal denaturation (structural destruction).
Slide No. 12
Chemical nature of enzymes
All enzymes are proteins with a molecular weight ranging from 15,000 to several million Da. All enzymes are proteins, but not all proteins are enzymes. Based on their chemical structure, they are divided into simple and complex (they have a non-protein part or a prosthetic group).
The functions of the prosthetic group are as follows: participation in the act of catalysis, contact between the enzyme and the substrate, stabilization of the enzyme molecule in space.
Slide No. 13
In the process of catalyzing a reaction, not the entire enzyme molecule, but a certain part of it, which is called the active center, comes into contact with the substrate. This zone of the molecule does not consist of a sequence of amino acids, but is formed by twisting the protein molecule into a tertiary structure. Individual sections of amino acids come closer to each other, forming a specific configuration of the active center.
In addition to the active center, a number of enzymes are equipped with a regulatory (allosteric) center. Substances that affect its catalytic activity interact with this zone of the enzyme.
Slide No. 14
Enzyme sizes and structure
The molecular weight of enzymes, like all other proteins, lies in the range of 10 thousand - 1 million (but may be more). They may consist of one or more polypeptide chains and may be represented by complex proteins. The latter, along with the protein component (apoenzyme), includes low-molecular compounds - coenzymes (cofactors, coenzymes), including metal ions, nucleotides, vitamins and their derivatives. Some enzymes are formed in the form of inactive precursors (proenzymes) and become active after certain changes in the structure of the molecule, for example, after the cleavage of a small fragment from it.
Many enzymes form so-called enzyme complexes. Such complexes, for example, are built into the membranes of cells or cellular organelles and are involved in the transport of substances. The cause of another hereditary disease - phenylketonuria, accompanied by a disorder of mental activity, is the loss of the ability of liver cells to synthesize the enzyme that catalyzes the conversion of the amino acid phenylalanine into tyrosine.
Determination of the activity of many enzymes in blood, urine, cerebrospinal, seminal and other body fluids is used to diagnose a number of diseases. Using this blood serum analysis, it is possible to detect myocardial infarction, viral hepatitis, pancreatitis, nephritis and other diseases at an early stage.
Slide No. 17
Human use of enzymes
Since enzymes retain their properties outside the body, they are successfully used in various industries. For example, papaya proteolytic enzyme (from papaya juice) - in brewing, to soften meat; pepsin - in the production of “ready-made” cereals and as a medicinal product; trypsin - in the production of baby food products; rennin (rennet from the stomach of a calf) - in cheese making. Catalase is widely used in the food and rubber industries, and cellulases and pectidases that break down polysaccharides are used to clarify fruit juices.
History of discovery
Enzymes were first discovered by the Russian chemist K.S. Kirchhoff in 1814.
Russian physiologist I.P. Pavlov
named enzymes
"Bearers of life."
DEFINITION:
- Enzymes or enzymes are organic catalysts of a protein nature that speed up reactions necessary for the functioning of organisms. Currently, 2000 enzymes are known.
Classification of enzymes
Enzyme classes
Catalyzed reaction
Transfer of atoms (n) or electrons from one substance to another.
Dehydrodegenase, oxidase.
Oxidoreductases
Tansmiraza,kin.aza
Transfer of a certain group of atoms (methyl, acyl, phosphate, amino) from one substance to another.
Transferases
Hydrolysis reactions
Lipase, amylase, peptidase.
Hydrolases
Isomerases
Isomerase, mutase.
Intramolecular rearrangement.
Non-hydrolytic addition to the substrate or detachment of a group of atoms from it. (C-C, C-N, C-O, or C-N bonds are broken
Decarboxylase, fumarase, aldolase
ENZYME PROPERTIES:
- Selectivity
- Efficiency
- Temperature dependence
- Dependence on the solution environment
Enzyme selectivity:
- Selectivity is the property of enzymes to accelerate only one or a group of similar reactions.
- Selectivity allows the body to quickly and accurately carry out a clear program for the synthesis of substances.
Enzyme efficiency:
- Efficiency is the property of accelerating a reaction. The speed of some enzymatic reactions can be 10-15 times greater than the speed of the reaction occurring in their absence......
Example: 2H 2 O 2 catalase 2H 2 O+O 2
Efficiency
depends on
Temperatures (highest at t 37 º )
Solution media (from pH) pepsin (pH – from 1.5 to 2) (0.9-2.0) saliva (pH –6.8)) (5.6-7.9) bile (pH – 6.8) (5.6-8.0) blood plasma (pH – 7.4) (7.25-7 .44) sweat (pH – 7.4) (4.2-7.8) deviation – the cause of diseases
Simple
Complex
Protein
component
Protein
component
non-protein
Part
coenzyme
How enzymes work
Enzyme and substrate must be suitable
to each other “like a key to a lock”
Substrate-substance
which is affected by
enzyme
Action of catalase (peroxidase) in raw meat
- PLACED INTO A TEST TUBE
HYDROGEN, ALL MEAT
COVERED WITH BUBBLES
GAS (O 2). (CHECKED THIS WITH
A smoldering splinter, it flared up.)
Action of catalase (peroxidase) of potato tuber
- GROUND POTATOES WERE MIXED WITH FINE CLEAN SAND AND HYDROGEN PEROXIDE ADDED, A RAPID RESOLUTION OCCURRED, GAS BUBBLES (O2) were released. THE REACTION HAPPENED VERY QUICKLY, BECAUSE THE ACTIVITY OF THE GRINDED POTATO TISSUE IS VERY HIGH.
Action of catalase (peroxidase) in green leaf cells
- GREEN LEAF CELLS WERE PLACED INTO A TEST TUBE AND PEROXIDASE ADDED, OXYGEN GAS FORMED IN THE TEST TUBE.
OXYGEN GAS RAISED GREEN CELLS
LEAF ABOVE SOLUTION.
TO CHECK WHAT IS STANDED OUT
GAS OXYGEN LET'S BRING A Smoldering Splinter
IT WILL START TO FLASH UP AT THE TEST TUBE
(BECAUSE OXYGEN SUPPORTS COMBUSTION).
Effect of cow's milk dehydrogenase on dye
DROPS OF METHYL BLUE AND
15 DROPS OF 0.5% FORMALDEHYDE SOLUTION.
DYE
IT IS GRADUALLY DISCOLORED.
HAPPENES BECAUSE TO HIM
HYDROGEN IS ADDED TO THE MOLECULE,
SELECTED FROM
FORMALDEHYDE INVOLVED
DEHYDROGENASE PHASE,
WHICH IS CONTAINED IN COW'S MILK.
Practical use
Brewery
Textile
Saccharification of the contents
starch in malt
Bakery
Removing starch applied to
threads during sizing
The bread browns better and does not go stale longer
Proteases (break down proteins)
Brewery
Steps in the brewing process that control foam quality
pharmaceutical
Tenderizing meat
Additives to toothpastes for removing plaque
Washing off gelatin
with used
films for
to extract
contained in it
Food - production of baby food products
Cheese making - milk curdling
(obtaining casein curd)
Pharmaceutical
Production of “ready-made” cereals
Digestive aids (in addition to the normal action of pepsin in the stomach)
Catalase
Hydrogen Peroxide Removal
Rubber
Obtaining (from hydrogen peroxide) the oxygen necessary to convert latex into sponge rubber
Bacterial proteases
Laundry
Tannery
Washing powders with enzyme additives
Textile
Hair separation is a method in which neither hair nor skin is damaged
Extracting wool from sheep skin scraps
Receipt
protein hydrolysates (for feed production)
1. Enzymes are called:
a) low molecular weight organic compounds necessary for the implementation of processes occurring in the body, b) natural protein catalysts that accelerate biochemical processes,
c) biologically active substances that are produced by the endocrine glands and regulate the activity of organs and tissues of a living organism,
d) biologically active substances that inhibit the vital activity of pathogenic microorganisms.
2. Match:
nature of the catalyst : 1) organic, 2) inorganic ;
characteristic property: a) high selectivity,
b) low relative molecular weight, c) protein nature, d) high efficiency.
3. Enzyme activity depends on:
a) temperature, b) acidity of the environment, c) presence of coenzyme,
d) all previous answers are correct.
Enzymes are catalysts and are characterized by all the principles of catalysis, but enzymes also have a number of unique properties that distinguish them from inorganic catalysts. This difference is explained by the protein nature of the enzyme.
A Tale of the Division of Inheritance
An old Arab was dying. All his wealth consisted of 17 beautiful white camels. He gathered his sons and announced to them his last will: “My eldest son, the support of the family, should receive half of the camels after my death. I bequeath a third of all camels to my middle son. But my youngest, beloved son should also receive his share - one ninth of the herd.” Having said this, the old Arab died. After burying their father, the three brothers began to divide the camels. But they could not fulfill their father’s will: it was impossible to divide 17 camels either in half, or into three parts, or into nine parts. But then a dervish passed through the desert. Poor, like all scientists, he led with him a black, shabby camel loaded with books. The brothers turned to him for help. And the dervish said: “It is very simple to carry out the will of your father. I give you my camel, and you try to divide the inheritance.” The brothers ended up with 18 camels, and everything was resolved. The eldest son received half of the camels - 9, the middle one - a third of the herd - 6 and the youngest son received his share - two camels. But 9, 6 and 2 give 17, and after dividing there was an extra camel - the scientist’s old, shabby camel. And the dervish said: “Give me back my camel for helping to divide your inheritance, otherwise I will have to drag the books across the desert myself.” This black camel is like an enzyme. He made possible a process that would have been unthinkable without him, and he himself remained unchanged. This is truly the main property of enzymes, and indeed of any catalyst. Enzymes are primarily catalysts.
Description of the presentation by individual slides:
1 slide
Slide description:
Presentation by chemistry teacher of the State Budgetary Educational Institution “KMT” Zalieva N.M. Enzymes. Classification of enzymes. Features of the structure and properties of enzymes.
2 slide
Slide description:
ENZYMES (from Latin fermentum - fermentation, leaven) are enzymes, specific proteins that increase the rate of chemical reactions in the cells of all living organisms. The science of enzymes is called enzymology.
3 slide
Slide description:
The term "enzyme" was coined in the 17th century by the chemist van Helmont when discussing the mechanisms of digestion. History of the study
4 slide
Slide description:
In the 19th century Louis Pasteur, studying the transformation of carbohydrates into ethyl alcohol under the influence of yeast, came to the conclusion that this process (fermentation) is catalyzed by a certain vital force (enzyme) located in yeast cells, and he believed that these “forces” are inseparable from the structure of a living cell yeast. History of the study
5 slide
Slide description:
Eustace Liebig and his supporters, defending the chemical nature of fermentation, believed that it was a consequence of the formation of soluble enzymes in the cells of microorganisms. Louis Pasteur believed that fermentation is caused only by living microorganisms and that the fermentation process is inextricably linked with their vital activity. History of the study In the mid-19th century. A debate broke out about the nature of fermentation.
6 slide
Slide description:
History of the study The discussion between Liebig and Pasteur about the nature of fermentation was resolved in 1897 by Eduard Buchner, who, by grinding yeast with infusorial soil, isolated from them a cell-free soluble enzyme preparation (zimaza), which caused alcoholic fermentation. In 1907, Buchner was awarded the Nobel Prize in Chemistry “for his research work in biological chemistry and his discovery of extracellular fermentation.” Over the next 10 years, several more enzymes were isolated, and the protein nature of the enzymes was finally proven.
7 slide
Slide description:
The enzymes were first isolated in crystalline form in 1926 by James Betcheller Sumner and John Howard Northrop. In 1946 they were awarded the Nobel Prize. History of the study James Betcheller Sumner John Howard Northrop.
8 slide
Slide description:
In 1961, a systematic nomenclature of enzymes was proposed by the International Biochemical Union Commission. Enzymes are divided into 6 groups according to the type of reaction they catalyze. The working name consisted of the name of the substrate, the type of catalytic reaction and the ending -ase. Example: lactan + dehydrogenation + aza = lactate dehydrogenase The previous names of pepsin and trypsin were retained for the known enzymes. Classification of enzymes
Slide 9
Slide description:
Classification of enzymes Classes of enzymes Catalyzed reaction Examples of enzymes or their groups Oxidoreductases Transfer of hydrogen atoms or electrons from one substance to another. Dehydrogenase, oxidase Transferases Transfer of a certain group of atoms - methyl, acyl, phosphate or amino group - from one substance to another Transaminase, kinase Hydrolases Hydrolysis reactions Lipase, amylase, peptidase Lyases Non-hydrolytic addition to a substrate or detachment of a group of atoms from it. In this case, C-C, C-N, C-O or C-S bonds can be broken Decarboxylase, fumarase, aldolase Isomerases Intramolecular rearrangement Isomerase, mutase Ligases The connection of two molecules as a result of the formation of new bonds, associated with the breakdown of ATP Synthetase
10 slide
Slide description:
Typically, enzymes are isolated from animal tissues, plants, cells and cultural fluids of microorganisms, biological fluids (blood, lymph, etc.). Genetic engineering methods are used to obtain some difficult-to-obtain enzymes. Obtaining enzymes.
11 slide
Slide description:
Structure of enzymes Enzymes Simple - proteins Complex - proteins non-protein part or prosthetic group - coenzyme The protein part is called apoenzyme The protein part is called apoenzyme
12 slide
Slide description:
The structure of enzymes Coenzymes can be considered as an integral part of the enzyme molecule. These are organic substances, among which there are: nucleotides (ATP, UMP, etc.), vitamins or their derivatives (TDP - from thiamine (B1), FMN - from riboflavin (B2), coenzyme A - from pantothenic acid (B3), NAD etc.) and tetrapyrrole coenzymes - hemes. The functions of the prosthetic group are as follows: participation in the act of catalysis, contact between the enzyme and the substrate, stabilization of the enzyme molecule in space.
Slide 13
Slide description:
Enzymes have 2 centers: the Active center and the Allosteric center. Structure of enzymes The active center (ACS) is a relatively small region located on the surface of the enzyme molecule, which is directly involved in catalysis. It consists of a unique combination of amino acid residues, ensures connection with the substrate and its further transformation. In ACP, they are distinguished: Substrate-binding center - a site that is responsible for complementary binding of the substrate and the formation of an enzyme-substrate complex. Catalytic center - directly involved in chemical reactions with the substrate.
Slide 14
Slide description:
An allosteric center is a combination of amino acid residues on the surface of an enzyme to which low molecular weight compounds (effectors) bind, the molecules of which differ from the substrates. The addition of an effector changes the tertiary structure and, accordingly, the configuration of ACP, thereby causing a decrease (inhibitors) or increase (activators) in activity. Enzymes that are affected by effectors are called allosteric. The structure of enzymes
15 slide
Slide description:
The structure of enzymes A substance whose chemical transformation is catalyzed by an enzyme is called a substrate
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Substrate is a substance on which an enzyme acts. The enzyme and substrate must fit each other “like a key to a lock.” The principle of enzyme action
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The act of catalysis consists of three successive stages. 1. Formation of an enzyme-substrate complex during interaction through the active center. 2. Binding of the substrate occurs at several points in the active center, which leads to a change in the structure of the substrate and its deformation due to changes in the bond energy in the molecule. This is the second stage and is called substrate activation. In this case, a certain chemical modification of the substrate occurs and it is converted into a new product or products. 3. As a result of such a transformation, the new substance (product) loses the ability to be retained in the active center of the enzyme and the enzyme-substrate, or rather, enzyme-product complex dissociates (breaks up). Types of catalytic reactions: A+E = AE = BE = E + B A+B +E = AE+B = ABE = AB + E AB+E = ABE = A+B+E, where E is the enzyme, A and B - substrates or reaction products. Mechanism of action of enzymes
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Enzymes have the properties of proteins, but also have features: 1. Dependence on pH 2. Dependence on temperature 3. High specificity of action 4. Ability to regulate – i.e. may be influenced by activators or inhibitors Enzymes or enzymes are designated by the letter E
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The optimum pH for most enzymes is 6.0-8.0. This is the pH value at which the enzyme exhibits maximum activity. Hydrogen ions can change the degree of ionization of the substrate, product, and enzyme. The optimum temperature for most enzymes is 38-40C; at 41-42C thermal denaturation occurs. When the temperature increases by 10C, the rate of the enzymatic reaction increases by 2 times. 1. Dependence on pH 2. Dependence on temperature Properties of enzymes
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The specificity of the action is determined by the structure of the active center of the enzyme and lies in the fact that each enzyme catalyzes the transformation of one substrate or a group of substrates that are similar in structure. 3. High specificity of action Properties of enzymes
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Properties of enzymes There are several types of specificity. Stereochemical substrate specificity - the enzyme catalyzes the conversion of only one stereoisomer of the substrate. For example, fumarate hydratase catalyzes the addition of a water molecule to the multiple bond of fumaric acid, but not to its stereoisomer, maleic acid. Absolute substrate specificity - the enzyme catalyzes the conversion of only one substrate. For example, urease catalyzes the hydrolysis of only urea. Group substrate specificity - the enzyme catalyzes the transformation of a group of substrates of similar chemical structure. For example, alcohol dehydrogenase catalyzes the conversion of ethanol and other aliphatic alcohols, but at different rates.
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Properties of enzymes 4. Ability to regulate Influence on the activity of enzymes by activators and inhibitors. Factors that increase enzyme activity include metal cations and some anions. Most often, enzyme activators are cations Mg2+, Mn2+, Zn2+, K+ and Co2+, and among anions - Cl-. Cations act on enzymes in different ways. In some cases, they facilitate the formation of the enzyme-substrate complex, in others they facilitate the attachment of the coenzyme to the apoenzyme, or they attach to the allosteric center of the enzyme and change its tertiary structure, as a result of which the substrate and catalytic centers acquire the most favorable configuration for catalysis.
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Inhibitors inhibit the action of enzymes. Inhibitors can be both endogenous and exogenous substances. The mechanisms of the inhibitory action of various chemical compounds are varied.
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Enzymes involved in the synthesis of proteins, nucleic acids and energy metabolism enzymes are present in all cells of the body. But cells that perform special functions also contain special enzymes. Thus, the cells of the islets of Langerhans in the pancreas contain enzymes that catalyze the synthesis of the hormones insulin and glucagon. Enzymes that are characteristic only of the cells of certain organs are called organ-specific: arginase and urokinase - liver, acid phosphatase - prostate. By changing the concentration of such enzymes in the blood, the presence of pathologies in these organs is judged. In a cell, individual enzymes are distributed throughout the cytoplasm, others are embedded in the membranes of mitochondria and the endoplasmic reticulum; such enzymes form compartments in which certain, closely interconnected stages of metabolism occur. Many enzymes are formed in cells and secreted into anatomical cavities in an inactive state - these are proenzymes. There are also isoenzymes - enzymes that differ in molecular structure, but perform the same function. Distribution of enzymes in the body
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Enzymes are widely used in the light, food and chemical industries, as well as in medical practice. In the food industry, enzymes are used in the preparation of soft drinks, cheeses, canned food, sausages, and smoked meats. In animal husbandry, enzymes are used in the preparation of feed. Enzymes are used in the production of photographic materials. Enzymes are used in the processing of oats and hemp. Enzymes are used to soften leather in the leather industry. Enzymes are included in washing powders and toothpastes. In medicine, enzymes have a diagnostic value - the determination of individual enzymes in a cell helps to recognize the nature of the disease (for example, viral hepatitis - by the activity of the enzyme in the blood plasma); they are used to replace the missing enzyme in the body. Application of enzymes
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Tests “Enzymes” 1. Enzymes are: A) regulators; B) catalysts; B) substrate activators; D) carriers of substances through the membrane; D) nerve impulse mediators. 2. Enzymes can only consist of: A) protein; B) protein and non-protein part; B) nucleotides; D) low molecular weight nitrogen-containing organic substances; D) lipids and carbohydrates. 3. A coenzyme is: A) an easily separated protein part of a complex enzyme; B) non-separable non-protein part of a complex enzyme; B) the protein part of a complex enzyme; D) non-protein part of a simple enzyme; D) a loosely bound non-protein part of a complex enzyme. Consolidating new material
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4. A prosthetic group is: A) the protein part of a complex enzyme; B) enzyme structure stabilizer; B) activator of a complex enzyme; D) non-protein part tightly bound to the enzyme; D) part of the enzyme that forms the catalytic center. 5. What is the name of the non-protein part of a complex enzyme responsible for catalysis? A) Coenzyme; B) Apoenzyme. 6. What class do enzymes belong to that catalyze reactions of transfer of functional groups and molecular residues from one molecule to another? A) Hydrolases; B) Transferases; B) Oxidoreductases; D) Isomerases.
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Homework 1. Creative task: prepare a presentation. 2. Abstract on the topic “Areas of application of enzymes”
