An enzyme has a total of four active sites.When you denature the molecule and study its composition,you find that each active site occurs on a different polypeptide.Which of the following hypotheses does this observation support?
A)The enzyme is subject to allosteric regulation.
B)The enzyme requires a cofactor to function normally.
C)The protein's structure is affected by temperature and pH.
D)The protein has quaternary structure.

Question

Quizplus · Accepted Answer

The observation that each active site occurs on a different polypeptide indicates that the enzyme has quaternary structure, meaning it is composed of multiple polypeptide subunits that come together to form a functional molecule with multiple active sites. This is only possible in quaternary structured proteins, and not in proteins with a primary, secondary, or tertiary structure alone. Therefore, the correct answer is D.

An Enzyme Has a Total of Four Active Sites