Write briefly about enzyme inhibitors.

Explanation

(a) The chemicals that block the enzyme activity are called inhibitors. The process is called inhibition.
(b) Inhibitors are three types. They are
(i) Competitive inhibitors
(ii) Non-competitive inhibitors
(iii) Feedback inhibitors
(i) Competitive inhibitors : These are the substances which are structurally similar to substrate molecules and compete for the active sites of an enzyme. Eg : Inhibition of succinic dehydrogenase by malonate which closely resembles the substrate succinate in structure.
(ii) Non-competitive inhibitors : These chemicals do not resemble the substrate in structure. They bind to an enzyme at locations other than the active sites and makes it inactive. So no new products are formed. Eg : Metal ions of copper, mercury, silver etc.
(iii) Feedback inhibitors : In many biochemical reactions, the accumulation of end products of reactions will inhibit the first step of reaction. It is a part of homeostatic control of metabolism.