Fig. 2.1 shows two types of enzyme inhibition. In the second type, the substrate still binds normally to the active site, but an inhibitor instead binds to a separate allosteric site on the enzyme, which changes the shape of the active site. What is this type of inhibition called?
AUncompetitive inhibition, where the inhibitor binds only to the enzyme-substrate complex
BNon-competitive inhibition, where the inhibitor binds a separate allosteric site
CCompetitive inhibition, where the inhibitor binds directly at the active site
DIrreversible inhibition, where the inhibitor permanently binds and denatures the enzyme
Explanation
The inhibitor binds to an allosteric site rather than the active site itself, altering the active site's shape so the substrate can no longer bind effectively; binding away from the active site while still disrupting substrate binding is what defines non-competitive inhibition.
Derived from ZIMSEC Biology Paper 2, June 2006, Q1