nucleotide metabolism Flashcards
prpp used in ?
synthesis of purine and pyrimidine nucleotides
carbomyl phosphate synthetase II used in?
carbomyl phosphate synthetase I used in?
catalyzation of first rxn in pyrimidine nucleotide synthesis
catalyzation of first rxn in urea cycle
TMP is formed from dUMP by?
action of thymidylate synthase
deoxyribonucleotides formed by?
rubonucleotide reductase on ribonucleoside diphosphates
pyrimide nucleotide synthesis rxns
1) CO2+glutamine+ATP—->(carbamoyl phosphate synthetase II) gives carbomyl phosphate + glutamate + aspartate
2) carbomylation of aspartate
3) orotic acid (pyrimadine structure) added to PRPP to give UMP which can synthesize CMP
3)UMP converts to UTP converts to CTP
4)
pyrimidine (orotic acid) added to PRPP forms?
pyrimidine mononucleotide
pyrimidine (orotic acid) decarboxylated forms?
UMP which CMP can. be synthesized
hereditary orotic aciduria
deficiency of orotate phosphoribosyltransferase accumulates orotic acid in blood and urine
adenosine deaminase deficiency
deficiency of adenosine deamninase casuses immunodeficiency
gout
abnormalities of purine enzymes result in high levels of uric acid causing painful depositionof uric acid in joints
purine nucleotide synthesis (AMP and GMP)
first purine nucleotide to be synthesized is inosine monophosphate (IMP) in which the purine is hypoxanthine.
IMP can be converted to form AMP and GMP
carbamoyl phosphate used for pyrimidine nucleotide
synthesis is derived from glutamine and
bicarbonate, within the cytosol, as opposed to the
Urea Cycle carbamoyl phosphate derived from
ammonia and bicarbonate in the mitochondrion
difference is glutamine in pyrimidine nucleotide in cytosol
and ammonia in urea cycle in mitochondria and both substrates react with bicarbonate
