salvage pathways

Question 1

purine salvage: what is it

Answer 1

when purines from cellular nucleic acid are turned over, or obtained from diet

Question 2

purine salvage pathway, enzymes involved

Answer 2

conversion of purine bases to nucleotides. adenine phosphoribosyltransferase (APRT)
and hypoxanthine-guanine phosphoribosyltransferase (HGPRT).

BOTH USE PRPP as their source of ribose 5 phosphate

Question 3

Lesch-Nyhan syndrome

Answer 3

x linked, recessive: complete deficiency of HGPRT
mnemonic: 
H: hyperuricemia
G: gout
P: pissed off (aggressive behavior)
R: retardation
T: dysTonia

Question 4

adenosine deaminase deficiency

Answer 4

major causes of autosomal recessive SCID (severe combined immunodeficiency)

in ADA deficiency. dATP–> lymphotoxicity

Question 5

the enzymes in purine salvage important to know for the diseases they cause, and drugs that act on them

Answer 5

1. HGPRT - absence in x linked recessive dis. –> uric acid build up –> hyperuricemia,
2. XO - xanthine oxidase - drug targets for allopurino/febuxostat
3. ADA - deficiency is major cause of SCID (dATP–> lymphtoxicity)
4. Resburicase - converts uric acid to urine. targets of aspirin (inhibits) and probenecid (stimulates)

Question 6

allopurinol

Answer 6

inhibits xanthine oxidase

Question 7

febuxostate

Answer 7

inhibits xanthine oxidase

Question 8

probenecid

Answer 8

stimulates resburicase to convert uric acid to urine

Question 9

aspirin

Answer 9

inhibits resburicase, preventing uric acid–> urine