試題詳解

47. Which of the following statements about the reactions involved in the synthesis of deoxyribonucleotides is false?
(A) Deoxyribonucleotides are derived from the corresponding ribonucleotides by direct reduction at the 2'-carbon atom of the D-ribose to form the 2'-deoxy derivative.
(B) Formation of deoxyribonucleotides is catalyzed by ribonucleotide reductase, in which its substrates are ribonucleoside diphosphates.
(C) Ribonucleotide reductase is notable in that its reaction involves free radicals in biochemical transformations.
(D) Nucleoside diphosphate kinase catalyzes the reaction: dTDP + ATP → dTTP + ADP.
(E) The immediate precursor of thymidylate (dTMP) is dUMP. The conversion of dUMP to dTMP is a reaction of deamination.