Question

Which of the following statement about enzyme inhibitors is incorrect?

• A. A competitive inhibitor binds the active site of the enzyme.
• B. An allosteric inhibitor binds a site on the active site of the enzyme.
• C. A noncompetitive inhibitor binds a site other than the active site.
• D. Noncompetitive inhibition cannot be completely overcomes by the addition of more substrate.

Answer 1

The correct option is B An allosteric inhibitor binds a site on the active site of the enzyme.

Competitive inhibition is caused by a competitive inhibitor which has structural similarity with the substrate of enzyme, so that both compete for binding at the active site of the enzyme. The non competitive inhibition does not depends on realtive concentration of substrate and inhibitors. Hence, it cannot be reversed by increasing the concentration of substrate relative to the inhibitor molecules. Allosteric enzymes are the enzymes which have an allosteric site in addition to the active site for binding of allosteric modulators.