Nucleotide Degradation and Salvage Pathways — Flashcards

Flashcard 1: Which enzyme is an alternative pathway for conversion of Adenine to AMP via the salvage pathway?_____

Answer: Adenine phosphoribosyltransferase (not HGPRT)

Flashcard 2: Inosine is converted to _____ via the enzyme purine nucleoside phosphorylase (purine salvage)

Answer: hypoxanthine

Flashcard 3: The enzyme _____ is an important enzyme for de novo purine production, which converts PRPP to an intermediate used in the generation of IMP

Answer: PRPP amidotransferase

Flashcard 4: Guanosine is converted to _____ via the enzyme purine nucleoside phosphorylase (purine salvage)

Answer: guanine

Flashcard 5: Besides its role in **thymidine** production, **THF** is also involved in the formation of _____, as well as some amino acids

Answer: purine nucleosides

Flashcard 6: Xanthine may be converted to _____ via the enzyme xanthine oxidase

Answer: uric acid

Flashcard 7: Orotic acid is combined with _____ to form UMP (pyrimidine synthesis)

Answer: phosphoribosyl pyrophosphate (PRPP)

Extra: This process is catalyzed by the bifunctional enzyme **UMP synthase**, which possesses both orotate phosphoribosyltransferase and OMP decarboxylase activities. Orotidine 5'-monophosphate (OMP) is the immediate intermediate formed before decarboxylation to UMP.

Flashcard 8: Pyrimidine synthesis begins with _____, CO2, and 2 ATP

Answer: glutamine

Flashcard 9: Hypoxanthine is converted to _____ via xanthine oxidase

Answer: xanthine