Question

Which of the following is true?
Non-competitive inhibitor differs from a competitive inhibitor in that it

• A. Reduces the affinity of substrate for enzymes
• B. Does not alter K${}_m$
• C. May attach it self to the enzyme at a site other than the active site
• D. Both B and C

Answer 1

The correct option is D Both B and C

A non-competitive inhibitor is one that binds to a site distinct from the site which binds the substrate; inhibitor binding does not block substrate binding or vice versa. The enzyme is inactivated when inhibitor is bound, whether or not substrate is also present. The inhibitor effectively lowers the concentration of active enzyme and hence, lowers the apparent V${}_{max}$. There is often little or no effect on K${}_m$.