Purine Flashcards
Fate of purine after it has served its purpose
most of it is degraded to uric acid and a small percentage is salvaged
Fate of pyrimidine after it has served its purpose
absorbed in the intestinal mucosa and returned to circulation
What is SCIDs (severe combined immunodeficiency)
it is a deficiency in ADA (adenosine deaminase)
what happens as a result of SCIDS
T cells and B cells cant synthesize DNA because of an accumulation of dATP
wha substrates are better for purine nucleoside phosphorylase
guanosine and inosine
enzyme used to go from hypoxanthine to xanthine then to uric acid
xanthine oxidase
what does PNP (purine nucleoside phosphorylase) deficiency impair
T cell function
PNP deficiency is characterized by
decreased uric acid formation and increased purine nucleosides and nucleotides
gout is characterized by
HYPERURICEMIA and acute arthritic joint inflammation caused by deposition of uric acid crystals
gout that is genetic and affects males over 30
primary gout (gout that is associated with overproduction of uric acid)
gout brought on by leukemia, polycythemia, HGPRT deficiency, treatment of cancer with antimetabolites, or chronic renal insufficiency
secondary gout
how do you diagnose gout
presence of monosodium urate crystals in synovial fluid seen under polarized light microscopy
how do you treat gout
allopurinol and colchicine which cause excretion of xanthine and hypoxanthine instead of urate
how is allopurinol used as a treatment of gout
it is a non competitive inhibitor of xanthine oxidase hence preventing the production of uric acid
how does colchicine treat gout?
inhibits migration of white cells to joints where uric acid crystals are phagocytized
