Enzymes are made up of proteins and cofactors. Cofactors include coenzymes, which are loosely bound organic molecules, and cofactors, which can be either tightly or loosely bound inorganic ions that help bind the enzyme and substrate. The active site of an enzyme contains the binding site and catalytic site - the binding site chooses and attaches the substrate, while the catalytic site carries out the chemical reaction. The rate of enzyme-catalyzed reactions is affected by temperature and pH - most enzymes function best within a limited temperature and pH range, and outside that range the enzyme can denature.

1. STRUCTURE OF ENZYMES
PRESENTEDBY :
….
VIVEKANAND COLLEGE KOLHAPUR

2. INTRODUCTION :
• ENZYMES:
• ENZYMES ARE BIOLOGICAL CATALYSTS.
• ENZYMES SPEED UP THE RATE OF THE BIOCHEMICAL REACTION.
• MOST ENZYMES ARE THREE DIMENSIONAL GLOBULAR PROTEINS
(TERTIARY AND QUATERNARY STRUCTURE).
• RNA SPECIES ACT AS ENZYMES ARE CALLED AS RIBOZYMES.

3. STRUCTURE OF ENZYMES:
• ENZYMES ARE MADE UP OF APOENZYME (PROTEIN) AND COENZYME
(NON-PROTEIN)
• COENZYME:
• NON PROTEIN ORGANIC COMPONENT.
• LOOSELY BOUND TO THE APOENZYME.
• ACTS AS A DONOR OR ACCEPTOR OF GROUP OF ATOM.
• EX. NAD ,FAD.

4. COFACTOR:
• NON PROTEIN INORGANIC COMPONENT.
• MAY BE TIGHTLY BOUND OR LOOSELY BOUND.
• BRINGING GROUP TO BIND ENZYMES AND SUBSTRATE.
• EX. METAL IONS LIKE CU+2,ZN+2,MG2+.

5. • NON PROTEIN COMPONENT FIRMLY ATTACHED TO PROTEIN.
• ORGANIC OR INORGANIC.
• EITHER COENZYME OR COFACTOR.
• REQUIRED FOR EFFECTIVE CATALYSIS.
• BIOCYTIN,FE AND CU, MO AND FE ETC.
PROSTHETIC GROUP :

6. ACTIVE SITE OF ENZYMES:
ACTIVE SITE
BINDING SITE CATALYTIC SITE
IT CHOOSES THE SUBSTRATE
AND BINDS IT TO ACTIVE SITE.
IT PERFORMS THE CATALYTIC
ACTION OF ENZYME.

7. SUBSTRATE:
• THE REACTANT IN BIOCHEMICAL REACTION IS TERMED AS
SUBSTRATE.
• WHEN A SUBSTRATE BINDS TO AN ENZYME IT FORMS AN ENZYME
SUBSTRATE COMPLEX.
SUBSTRATE JOINS ENZYME

8. FACTORS AFFECTINGRATE OF ENZYME CATALYSED
REACTIONS:
• TEMPERATURE
• HYDROGEN ION CONCENTRATION

9. EFFECT OF TEMPERATURE:
• RAISING THE TEMPERATURE INCREASES THE RATE OF ENZYME
CATALYZED REACTION BY INCREASING KINETIC ENERGY OF REACTING
MOLECULES .
• ENZYMES WORKS MAXIMUM OVER A PARTICULAR TEMPERATURE
KNOWN AS OPTIMUM TEMPERATURE.
• HOWEVER SOMETIMES HEAT ENERGY CAN ALSO INCREASE KINETIC
ENERGY TO A POINT THAT EXCEED THE ENERGY BARRIER WHICH
RESULTS IN DENATURING OF ENZYMES.

11. EFFECT OF PH:
• RATE OF ALMOST ALL ENZYMES CATALYZED REACTIONS DEPENDS ON
PH.
• MOST ENZYMES EXHIBIT OPTIMAL ACTIVITY AT PH VALUE BETWEEN 5
AND 9.
• HIGH OR LOW PH VALUE THAN OPTIMUM VALUE CAUSE IONIZATION
OF ENZYME WHICH RESULTS IN DENATURATION OF ENZYME .