Glutamine phosphoribosyl pyrophosphate amidotransferase catalyzes step 2 in the biosynthesis of purines. Which of the following is a true statement regarding the regulation of this enzyme?
A) It is accelerated by an input of ATP or GTP.
B) It is sensitive to activation by azaserine.
C) It is accelerated by an input of AMP or GMP.
D) The G series of nucleotides as well as the adenine nucleotides act as competitive inhibitors.
E) It is subject to feed-forward activation by ADP.

Question

Quizplus · Accepted Answer

The enzyme glutamine phosphoribosyl pyrophosphate amidotransferase is subject to feedback inhibition by the end products of its pathway, which include the G series of nucleotides (guanine nucleotides) and the adenine nucleotides. These nucleotides act as competitive inhibitors, binding to the enzyme and preventing its action, thus regulating the biosynthesis of purines according to the cell's needs.

Glutamine Phosphoribosyl Pyrophosphate Amidotransferase Catalyzes Step 2 in the Biosynthesis