Question

Statins lower cholesterol levels by:

a. inhibiting fatty acid synthase.

b. preventing formation of LDL.

c. inhibiting HMG-CoA reductase.

d. causing lipoproteins in the blood to disintegrate.

Answer 1

Ans. HMG-CoA --------------HMG-CoA reductase--------> Mevalonate --------> Cholesterol

Under normal physiological conditions, HMG-CoA reductase converts its substrate into mevalonate. The product of this reaction, mevalonate, is further converted into cholesterol.

Because of being structurally similar to the substrate HMG-CoA, statin competes for the active site of the enzyme HMG-CoA reductase. This competitive inhibition of the enzyme by statin reduce the rate of production of mevalonate and subsequently cholesterol, too.