Nucleotide Metabolism Flashcards
Rate limiting step in pyrimidine synthesis
ATCase
Inhibits ATcase
CTP
Stimulates ATcase
ATP
Inhibits conversion of IMP to guanosine derivatives-Treats cancer
Binds more tightly to folate than folic acid (acts as competitive inhibitor)
Methotrexate
Inhibits conversion of UMP to Thymidine-Used to treat cancer
5 Fluorouracil
Antiviral drug that resembles guanine. Viral TK converts this drug, which becomes a surrogate for GTP and is incorporated into rapidly dividing viral cells. Leads to termination of DNA replication. Treats herpes zoster and chickenpox
Acyclovir
Catabolism makes succinyl and malonyl coA
Pyrimidine
Caused by overproduction of uric acid. Treated by allopurinol
GOUT
Mechanism of action is to inhibit xanthine oxidase
Allopurinol
Salvage pathway that involves TK (DTTP)
Produces UTP from uracil
Pyrimidine Salvage Pathway
Salvage pathway that makes AMP from Adenine and GMP and IMP from Guanine and Hypoxanthine
VIA HGPRT
Purine Salvag pathway
Defect in HGPRT; can’t make IMP or GMP; leads to accumulation of uric acid; High levels of hypoxanthine and guanine shunted towards uric acid instead of being used in the salvage pathwayMental retardation and self mutilation
Lesch-Nyhan
Rate limiting enzyme in purine synthesis and what step?
Glutamine
Converting PRPP to PRA
Rate limiting enzyme in pyrimidine synthesis and what step?
ATCase
Converting Carbonyl phosphate to carbonyl aspartate