試題詳解

11. Which of the following statements is correct regarding the biosynthesis of purine nucleotides?
(A) Glycine, aspartate, and glutamine serve as nitrogen sources for the purine ring.
(B) The concentration of 5-phosphoribosyl 1-pyrophosphate is the major factor regulating the rate of de novo purine nucleotide biosynthesis.
(C) Lesch-Nyhan syndrome is caused by a defect in hypoxanthine-guanine phosphoribosyl transferase, an enzyme involved in purine salvage.
(D) AMP and GMP inhibit hypoxanthine-guanine phosphoribosyl transferase, which converts hypoxanthine and guanine into IMP and GMP.
(E) All of the above are correct.