Regulation Of Enzyme

REGULATION OF ENZYMES

• Mechanism for regulating the enzyme activity-

1. Allosteric modulation
2. Covalent modification
3. Induction and repression of enzyme synthesis 

Allosteric modulation-

• Allosteric Enzymes have a catalytic site where the substrate binds and a separate site where a modifier binds.
• Examples-

Covalent Modification-

• The most common covalent modification is the addition or removal of a phosphate group.
• Two types-

1.  Irreversible- partial proteolysis/ zymogen activation
2. Reversible- addition/ removal of a particular group.

• Methods of Reversible covalent modifications-

1. Phosphorylation/ dephosphorylation (most common)
2. Methylation
3. Adenylation
4. ADP reibosylation
5. Acetylation

• Protein kinase mostly add phosphoryl group to a serine, threonine or tyrosine.
• Specific activity– number of enzyme units per milligram of protein.
• Catalase has the highest turnover number and hence is the fastest active enzyme.