Main subjects:
2.1. Special features of enzymatic catalysis
2.2. Properties of enzymes
2.3. Kinetics of enzymatic reactions
2.4. Coenzyme function of vitamins
2.5. Enzyme classification
2.6. Regulation of enzyme activity
2.7. Enzyme inhibitors
2.8. Application of enzymes in medicine
The conversion of different molecules in the body is catalyzed by enzymes. Under conditions characteristic of a living organism these reactions would be catalyzed very slowly without enzymes, that is why practically all of them occur with the participation of biological catalysts.
Each enzyme is able to catalyze only a limited number of reactions, often just the only one. Enzymes are the proteins that have specific primary, secondary, tertiary and sometimes quaternary structures. Proteins can be classified as simple or conjugated. If the enzyme is a conjugated protein its nonprotein part is referred to as a cofactor, or coenzyme, and protein part - as an apoenzyme. The apoenzyme combined with the coenzyme form the active catalyst - holoenzyme:
Apoenzyme + Cofactor → Holoenzyme (Coenzyme)
The activity of enzymes, their ability to accelerate the reactions depend on the extent of the protein?s native structural integrity. When native conformation is damaged, for example by heating, as a result of abrupt
pH changes or by effect of denaturation agents, enzymes lose their catalytic properties. The majority of enzymes exhibit their activity in aqueous (water) solution at physiologic pH and temperature values.
2.1. SPECIAL FEATURES OF ENZYMATIC
CATALYSIS
Enzymes possess high specificity and increase the rate of the exactly determined biochemical reactions. Enzymes do not alter the equilibrium of the reactions accelerated by them, they are not consumed in the course of the reaction and do not undergo irreversible changes (Fig. 2.1).