Nucleotide Synthesis Flashcards
rate limiting enzyme of purine synthesis
PRPP glutamyl amidotransferase
a rate limiting enzyme of pyrimidine synthesis
carbamoyl phosphate synthetase II
donors of atoms
in purine synthesis
- glutamine
- aspartate
- carbon dioxide
- glycine
- N10-formyltetrahydrofolate
donor of ribose-5 phosphate
to purine and pyrimidine synthesis
PRPP
sequence of steps
in purine synthesis
preformed ribose-5-phosphate comes then
–>
purine ring is constructed
parent molecule
purine
inosine monophosphate
products
purine synthesis
IMP –> GMP
•requires ATP
IMP –> AMP
•requires GTP
donors of atoms
in pyrimidine synthesis
glutamine
aspartate
carbon dioxide
sequence of steps
in pyrimidine synthesis
pyrimidine ring is constructed first, then attached to ribose-5-phosphate
parent molecule
pyrimidine
orotidine monophosphate
products
of pyrimidine synthesis
•UMP –> UTP –> CTP
•UMP –> dUMP
ribonucleotide reductase
•dUMP –> TMP
(thymidylate synthase)
converts ribose-5-phosphate
to its activated form
5-phosphoribosyl-1- pyrophosphate (PRPP)
PRPP synthetase
energy requirement of PRPP synthetase
ATP –> AMP
multisubunit enzyme that reduces nucleoside diphosphates into their deoxy forms
ribonucleotide reductase
ribonucleotide reductase requires
thioredoxin
NADPH
