Which of the following statements is NOT correct concerning the regulation of the purine biosynthetic pathway?
A)PRPP competitively inhibits the enzyme Gln:PRPP amidotransferase.
B)ADP and GDP are feedback inhibitors of ribose-5-phosphate pyrophosphokinase.
C)"A" and "C" nucleotides allosterically inhibit glutamine phosphoribosyl pyrophosphate amidotransferase (Gln:PRPP amidotransferase).
D)The rate of IMP formation is dependent on the levels of the adenine and guanine nucleotides produced.

Question

Quizplus · Accepted Answer

PRPP (Phosphoribosyl pyrophosphate) is actually a substrate for the enzyme Gln:PRPP amidotransferase, not a competitive inhibitor. This enzyme catalyzes the first committed step in purine nucleotide biosynthesis, and its activity is regulated by feedback inhibition by the end products (such as AMP, GMP, and IMP), not by competitive inhibition by its substrate.

Which of the Following Statements Is NOT Correct Concerning the Regulation