Nucleotides Flashcards
nucleotide
base + ribose + one or more phosphate
while nucleoside is only base + ribose
what does the absence of HGPRT in salvage pathways cause
Lesch-Nyhan syndrome
-symptoms: gout, mental retardation, and self mutilation
T/F: Synthesis of deoxyribonucleotides are synthesized de novo
FALSE They are not synthesized de novo, instead they’re formed from existing ribonucleotides
what inhibits the overall activity of the enzyme: ribonucleotide reductase
by binding of dATP
what three factors control the substrate specificity in the synthesis of Deoxyribonucleotides
a) binding of dATP or ATP –> promotes reduction of UDP and CDP
b) binding of dTTP promotes reduction of GDP and inhibits reduction of UDP and CDP
c) binding of dGDP promotes reduction of ADP
the enzyme ribonucleotide reductase acts on what
all four nucleoside diphosphates
ADP GDP UDP CDP
two ways dUMP can be made
- dUDP phosphorylated to –> dUTP cleaved to –> dUMP and PPi
- dCDP (dephosphorylated to) –>dCMP(deaminated to) –> dUMP
what inhibits thymidylate synthase
F-dUMP
from flurouracil and fluorodeoxyuridine
which will ultIMATELY BLOCK DNA synthesis bc dT needed from synthesis
what inhibits dihydrofolate reductase
aminopterin
amethopterin (methotrexate)
will also block DNA synthesis
what are the xanthine oxidase reactions
turns
hypoxanthine –> xanthine -> uric acid
what is the xanthine oxidase inhibitor
allopurinol
what is allopurinol used to treat
gout bc it’s a pognant inhibitor of xanthine oxidase which creats uric acid and gout is uric acid build up
list the nucleoside analogues used in cancer or antiviral therapies
acylclovir ganciclovir 5-iododeoxyruidine AraA AraC AZT dideoxy C and I
what do acyclovir, ganciclovir, and 5 iododeoxyuridine treat
herpes
what do Ara A treat
viral encephalitis
