Characterization of the Complete Three-Dimensional Structure of a Newly Purified

Multiple Choice

Characterization of the complete three-dimensional structure of a newly purified protein suggests that it catalyzes the breakdown of a large substrate. The protein consists of a single polypeptide chain. It has a large pocket that appears to be the binding site for the substrate and a smaller indentation that appears to be the binding site for a regulatory molecule. What do these structural observations suggest about the mechanism by which the activity of this protein is likely regulated?

A) It is probably an enzyme that is regulated by noncompetitive inhibition.
B) It is probably a multi-subunit enzyme that is regulated by allosteric regulation.
C) It is probably an enzyme that is regulated by competitive inhibition.
D) It is probably an enzyme that is regulated by cooperativity.