Lecture 16 Flashcards
importance of PRPP in purine and pyrimidine metabolism
great LG, allowing for things to be added
PRPP stands for
5-phosphoribosyl-1-pyrophosphate basically 2 phosphates connected to each other
general way that purine nucleotides are made
add a nitrogen to PRPP to create insinuate (IMP) which is then modified and eventually leads to making GMP and AMP → mainstream nucleotides in building DNA and RNA
general way to make pyrymidine nucleotide
a base is made and added to PRPP,
aspartate reacts with carbamoyl phosphate t make carbamoyl aspartate (almost a purine ring) then dihydroratate and finally oratate this ring modified into our familiar friends
de novo synthesisof purines/ pyrimidines
newly made from smaller components AA
made over yonder
pyrimidines
so oratate is made “off of the ribose” and the added to PRPP
made upon the ring
purines
salvage pathway of purine/pyrimidine
bases are taken from eating sources and the purines get digested and then added onto PRPP to build stuff
Lesch-Nyan disease
pediatric genetic syndrome: problematic gene that has behavioral and dietary problems
what is gout?
uric acid deposit in joints causing big lumps
the enzyme xanthine oxidase is too active
caused by a single enzyme so there are lots of inhibitors
action of allopurinol
inhibits the xanthine oxidase (gout)
role of ribonucleotide reductase
uses reducing equivalents to form an oxidized/reduced form of either glutaredoxin or thioredoxin to reduce RNA into DNA bases deoxy
thymidylate synthase
adds methyl group to dUMP to make → dTMP
DHFR
enzyme that catalyses the rxn of takind tetrahydrofolate → dyhydrofolate.
chemotheraputics block this enzyme, slowing down DNA synthesis and cell proliferation
methotrexate action
block DHFR DNA synthesis, very helpful in cancer kill cells
