Roth

Question 1

which drug used for trx of patient with overproduction of uric acid

Answer 1

allopurinol

inhibits xanthine oxidase

Question 2

lesh nyhan

• inheritance
• sx

Answer 2

x linked r

hyperuricemia, spastic cerebral palsy, MR, self mutilation

Question 3

3 AA to synthesize purine ring

Answer 3

glycine, aspartate, glutamine

Question 4

enzyme deficient in selective T cell immunodef

Answer 4

purine nucleoside phosphorylase

Question 5

What enzmye is inhibited by…

• 5-FU
• Methotrexate
• Hydroxyurea

Answer 5

TS-thymidilate synthase
-makes dTTP

DHFR-Dihydrofolate reductase

RR-ribonucleotide reductase-makes dXTP

Question 6

Absnece of which enzyme leads to accumulation of metabolites in purine salvage pathway leading to SCIDS

Answer 6

ADA-adenosine deaminase

Question 7

absence of this enzyme leads to lesich nyhan

Answer 7

hgprt-hypoxanthine guanine phosphoribosyltransferase

no base salvage of hypoxanthine or guanine

Question 8

PRPP synthetase inhibitors

Answer 8

purne di/tri nucleotides

Question 9

committed step of purine syntehsis?

Answer 9

Synthesis of phosphoryibosylamine from PRPP bt PRPP amidotransferase

Question 10

De novo purine synthesis results in

Answer 10

IMP

Question 11

@ IMP syntehsis-what can be formed

Answer 11

AMP and GMP

Question 12

What kind of regulators are AMP and GMP of thier synthesis

Answer 12

negative

Question 13

trimethoprim mechanism

Answer 13

inhibts bacteria DHFR

Question 14

Folic acid analog mechanism and result

Answer 14

Inhibits DHFR
-purine and TMP syntehsis

no DNA synthesis-cell death

Question 15

purine salvage function

Answer 15

take purine bases and turn into nucleoside phosphate residues to recycle

Question 16

2 enzymes in purine salvage

Answer 16

HGPRT and APRT

Question 17

ADA def results in

Answer 17

SCID

Question 18

HGPRT def results in

-Sx?

Answer 18

Lesch Nyhan

-self mutilation, AR, aggresion, hyperuricemia, gout

Question 19

possible causes of gout

Answer 19

Lesch Nyhan, PRPP excess, decresaed uric acid excretion, G6PDH def, some diuretics

Question 20

allopurinol results in increased levels of

-what is special about these

Answer 20

hypoxanthine and xanthine

-dont crystalize

Question 21

pyrimidine synthesis comitted step

Answer 21

carbomyl phosphate fomration

Question 22

CPS1 vs CPS2

Answer 22

1 depends on N-acetylglutamate as allosteric activator

• invovled in urea cycle
• in mitochondria
• utilize NH3 as nitrogen source

2

• invovled in pyrimidine syn
• cytosol
• utilizes gamma amide group of glutamine as N source

Question 23

UMP becomes

Answer 23

UTP, CTP

dUMP, TMP

Question 24

what enzyme makes ribonucleotides to deoxyribonucs

Answer 24

ribonucleotide reductase

Question 25

what inhibits RR

Answer 25

dATP/hydroxyurea

Question 26

enzyme def in orotic aciduria

-wgat accumulates

Answer 26

UMP synthase
-contains both ortate phosphoribosyl transferase and OMP decarboxylase activites

orotate accumulates

Question 27

how trx orotic aciduria

Answer 27

uridine and cystidine