Lecture 3 Flashcards
(17 cards)
what does PRPP stand for?
5-Phosphoribosyl pyrophosphate
process of purine synthesis (ATP)
ribose-5-phosphate + ATP —-> PRPP —-> phosphoribosyl beta 1 amine —-> (9 steps) —-> IMP —-> adenylosuccinate —-> AMP + ATP —-> ADP + Pi —-> ATP
process of purine synthesis (GTP)
ribose-5-phosphate + ATP —-> PRPP —-> phosphoribosyl beta 1 amine —-> (9 steps) —-> IMP —-> XMP + ATP —-> GMP —-> GDP —-> GTP
what are the enzymes involved in ATP purine synthesis
adenylate kinase and ATP synthase
what are the enzymes involved in GTP purine synthesis
guanylate kinase and non-specific nucleoside diphosphate kinase
allosteric regulators in ATP synthesis
ADP, AMP, ATP regulate PRPP to to phosphoribosyl beta amine
ADP regulates ribose 5 phosphate to PRPP
allosteric regulators in GTP synthesis
GMP, GDP, GTP regulate PRPP to phosphoribosyl beta 1 amine
GDP regulates PRPP to phosphoribosyl beta 1 amine
pyrimidine synthesis
orotate + PRPP —-> OMP —-> UMP + ATP —-> UDP + ATP —-> UTP + ATP —-> CTP
orotate synthesis (involved in the synthesis of UTP and CTP
HCO3- + Glutamine + H2O + 2 ATP —-> carbamoyl phosphate + aspartate —-> orotate
competitive inhibition in ATP synthesis
AMP inhibits IMP —-> Adenylosuccinate
competitive inhibition in GTP synthesis
GMP inhibits IMP —-> XMP
allosteric inhibition in pyrimidine synthesis
UDP and UTP inhibit glutamine to carbamoyl phosphate
allosteric activation in pyrimidine synthesis
PRPP activates glutamine —-> carnbamoyl phosphate
ribonucleotide reductase makes dNDPs
- reduces NDP to dNDP
what is meant by “balancing” nucleotides
relative amounts of the nucleotides (wouldn’t have equal amounts of everything, its referring to relative amounts of the nucleotides)
why is nucleotide metabolism a target of cancer therapies
they target fast growing cells- ensure that they are not adequately able to produce nucleotides to slow down growth of cancer cells
why do women take folate (vitamin B) when pregnant
it is a component in nucleotide synthesis (it is a part of IMP)
