Question

What are enzyme inhibitors? Classify them on the basis of their mode of attachments on the active site of enzymes. With the help of diagrams explain how do inhibitors inhibit the enzymatic activity.

Answer 1

Enzymes are responsible to hold the substrate molecule for a chemical reaction and they provide functional groups which will attack the substrate to carry out the chemical reaction. Drugs which inhibit any of the two activities of enzymes are called enzyme inhibitors.

Enzyme inhibitors can block the binding site thereby preventing the binding of the substrate to the active site and hence inhibiting the catalytic activity of the enzyme.

Drugs Inhibit the attachment of natural substrate on the active site of enzymes in two different ways as explained below

(i) Drugs which compete with the natural substrate for their attachment on the active sites of enzymes are called competitive inhibitors.

(ii) Some drugs bind to a different site of an enzyme called allosteric site. It changes the shape of the active site and substrate cannot recognize it. Such enzymes are called non-competitive inhibitor the bond formed between the enzyme and an inhibitor is strong covalent bond then enzyme is blocked permanently.