This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Mechanisms for regulating enzyme activity are ALL EXCEPT 
Select and explain. 
A. Covalent modification, B. Allosteric activation, C. Competitive inhibition, D. Induction of genes for enzyme synthesis
C: Competitive inhibition
Answer: C: Competitive inhibition 
Explanation: Ans. is (c) Competitive inhibition [Ref: Harper 319`Ve p. 89-94; Lippincott 6"/e p. 62-64; Vasudevan 5thie p. 42-50; ShindeAs the name suggests, there is competition between inhibitor and normal substrate for the catalytic binding site of the enzyme. This is because both the inhibitor and the normal substrate have similar structural configuration. Therefore, enzyme cannot differentiate these two and both can bind to the enzyme. Both ES and EI complexes are formed. But only ES can form product.