Isoenzymes And Enzyme Regulation

Isoenzymes And Enzyme Regulation

Question 1. Define isoenzymes. Name them & give their clinical importance (or) LDH Isoenzymes
Answer:

Definition Isoenzymes:

• Isoenzymes are the multiple forms of an enzyme catalyzing the same reaction

Isoenzymes Examples:

Question 2. Define competitive inhibition. Give three examples (or) Features & examples of competitive & feedback inhibitions.
Answer:

Competitive Inhibition Definition:

1. The inhibitor which is structurally similar to the tire substrate competes with the Ore substrate for the binding site.
2. This diverts the enzyme to form enzyme- inhibitor complex instead of an enzyme-substrate complex.
3. This complex does not produce any products & remains stable
4. It results in the prevention of further enzymatic activity.
5. This is known as competitive inhibition.

Competitive Inhibition Features:

• It can be reversed by adding an excess substrate which will dislodge the inhibitor molecules
• The action of drugs depends upon the inhibitor present

Competitive Inhibition Examples:

Feedback Inhibition:

• It is a specialized type of allosteric inhibition necessary to control metabolic pathways for efficient cellular functions.
• Example: Aspartate transcarboxylase, ATCase
• Carbamoyl phosphate undergoes a sequence of reactions for the synthesis of the end product cytidine triphosphate, CTP.
• When CTP accumulates, it allosterically inhibits the enzyme ATCase
• This is called feedback inhibition