In mammals CPS-II is the regulated step on pyrimidine biosynthesis; however, in bacteria ____ is the regulated step.
A) dihydroorotase
B) aspartate transcarbamoylase (ATCase)
C) OMP decarboxylase
D) dehydroorotate dehydrogenase
E) none are true

Question

Quizplus · Accepted Answer

In bacteria, the rate-limiting step in pyrimidine biosynthesis is typically the regulation of aspartate transcarbamoylase (ATCase), which catalyzes the second step in de novo pyrimidine biosynthesis. This enzyme is regulated by feedback inhibition by the end-product, CTP.

In Mammals CPS-II Is the Regulated Step on Pyrimidine Biosynthesis;