Thymine nucleotides are not synthesized directly by cells but indirectly from other pyrimidine deoxyribonucleotides. All of the following statements regarding thymine nucleotide synthesis are true EXCEPT: A) dUMP is the immediate precursor for dTMP. B) The action of dUTPase allows dUTP to serve as a substrate in DNA synthesis. C) Thymidylate synthase catalyzes the formation of dTMP from dUMP. D) The methyl donor in the reaction of dTMP is N⁵, N¹⁰-methylene-THF. E) THF is used as a cofactor.

Question

Quizplus · Accepted Answer

The action of dUTPase prevents dUTP from being incorporated into DNA and promotes the use of dTTP instead. Thymine nucleotides are synthesized indirectly from other pyrimidine deoxyribonucleotides through the methylation of dUMP to form dTMP, which is catalyzed by thymidylate synthase. The methyl donor in this reaction is 5,10-methylene-THF. THF is used as a cofactor in this reaction.

Thymine Nucleotides Are Not Synthesized Directly by Cells but Indirectly