An enzyme is composed of four identical subunits. Binding of substrate to one subunit stimulates more rapid binding of substrate to each of the other three subunits. This enzyme is most likely regulated by which of the following mechanisms?
A) noncompetitive inhibition
B) competitive activation
C) competitive inhibition
D) cooperativity

Question

Quizplus · Accepted Answer

This enzyme exhibits cooperativity, a regulatory mechanism where the binding of a substrate to one subunit of an enzyme increases the affinity of the other subunits for the substrate. This is seen in enzymes with multiple binding sites, where the binding of a substrate to one site affects the activity at other sites, often leading to a more rapid and efficient catalysis.

An Enzyme Is Composed of Four Identical Subunits