A Commonality Between Type I and Type II Topoisomerases Is

Question

A commonality between type I and type II topoisomerases is that they both:
A) change the linking number in increments of 1 or 2.
B) require ATP.
C) go through a mechanism using a covalent enzyme-substrate intermediate.
D) are inhibited by quinoline antibiotics.
E) All of the answers are correct.

Accepted Answer

Both type I and type II topoisomerases use a covalent enzyme-substrate intermediate in their mechanism of action. While they differ in the details of this mechanism, this is a commonality between the two types. Choice A is only true for type I topoisomerases, and choice B is not always true for either type. Choice D is only true for type II topoisomerases, but even then not all quinoline antibiotics inhibit them. Therefore, the best choice is C.