High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of ________.
A) competitive inhibition
B) allosteric regulation
C) the specificity of enzymes for their substrates
D) positive feedback regulation

Question

Quizplus · Accepted Answer

This is an example of allosteric regulation, since the binding of citric acid at a different location from the active site changes the enzyme's shape and activity. It is not competitive inhibition, as the inhibitor (citric acid) is not competing with the substrate for binding to the active site. It is also not an example of the specificity of enzymes for their substrates or positive feedback regulation.

High Levels of Citric Acid Inhibit the Enzyme Phosphofructokinase, a Key