The pyrimidine ring system is shown below.What is the source of the N-1 during the de novo biosynthesis of pyrimidines?

Question

Quizplus · Accepted Answer

Aspartate is the source of the N-1 during the de novo biosynthesis of pyrimidines. Specifically, aspartate donates an amine group to carbamoyl phosphate, which begins the biosynthesis pathway. Urea and asparagine are not directly involved in the biosynthesis of pyrimidines. IMP (inosine monophosphate) is an intermediate in the biosynthesis of purines, not pyrimidines.

The Pyrimidine Ring System Is Shown Below