Nucleic Acids Flashcards
what is PRPP used in?
- de novo synthesis of purine/pyrimidines
- salvage of purine/pyrimidines
- synthesis of NAD from tryptophan
NAD is from which amino acid?
tryptophan
where on PRPP does building start?
C1 (anomeric carbon)
where does the ribose 5- phosphate used to make PRPP come from?
pentose phosphate pathway
what is the rate determining step of purine synthesis?
PRPP to 5-phosphoribosyl 1-amine
what enzyme is involved in the rate determining step of purine synthesis?
glutamine phosphoribosyl amidotransferase
what activates the rate determining step of purine synthesis?
PRPP
what other things are involved in the rate determining step of purine synthesis?
- glutamine
- H2O
what enzyme does allopurinol inhibit?
xanthine oxidase
Gout management
- NSAIDS
- Dietary changes
- Colchicine
- Probenicid
- Allopurinol
symptoms of Lesch-Nyhan Syndrome
HGPRT
H- Hyperuricemia G- Gout P- Pissed off (aggressive/self mutilation) R- Retardation T- dysTonia (spasticity)
what is the first step in pyrimidine biosynthesis?
formation of carbamoyl phosphate
what inhibits CPS II?
UTP
what activates CPS II?
PRPP
what is the nitrogen source for CPS II?
glutamine
what is the nitrogen source for CPS I?
ammonia
CPS II location
cytosol
CPS I location
mitochondria
how many ATP does CPS II use?
2 ATP
what is the order of enzymes for forming UMP from aspartate and carbamoyl phosphate?
1- Aspartate trans carbamoylase
2- Dihydroorotase, Dihydroorotate dehydrogenase
3- Orotate phosphoribosyl transferase
4- Orotate monophosphate decarboxylase
deficiency in what enzyme(s) causes increase in orotic acid
- orotate phosphorybosyl transferase
- OMP decarboxylase
what enzyme does 6-mercaptopurine eventually act on?
inhibits amido transferase
what enzyme does 5-flurouracil eventually act on?
inhibits thymidylate synthase (irreversibly)
