Which of the Following Statements Is NOT Correct Concerning the Regulation

Multiple Choice

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.