nucleotide metabolism

Question 1

rate limiting enzyme in purine synthesis

Answer 1

guanine phosphoribosyl aminotransferase

Question 2

PRPP synthetase is decreased in what syndrome

Answer 2

Arts Syndrome

Question 3

Mycophenolic acid and ribavirin block which enzyme in purine synthesis

Answer 3

IMP dehydrogenase

Question 4

methotrexate

Answer 4

blocks dihydrofolate reductase in folate synthesis to dihydrofolate and tetrahydrofolate

Question 5

PRPP synthetase is inhibited by

Answer 5

ADP and GDP

Question 6

PRPP synthetase is stimulated by

Answer 6

Pi

Question 7

Guanine phosphribosyl aminotransferase is inhibited by

Answer 7

AMP and GMP

Question 8

Guanine phosphriboysl aminotransferase is stimulated by

Answer 8

PRPP

Question 9

which enzyme IMP –> XMP

Answer 9

IMP dehydrogenase

Question 10

which enzyme XMP –> GMP

Answer 10

GMP synthetase

Question 11

which enzyme GMP –> GDP

Answer 11

guanylate synthetase

Question 12

which enzyme GDP –> GTP

Answer 12

nucleotide diphosphate kinase

Question 13

which enzyme AMP –> ADP

Answer 13

adenine synthetase

Question 14

which enzyme ADP –> ATP

Answer 14

nucleotide diphosphate kinase

Question 15

which enzyme IMP –> adenyl succinate

Answer 15

adenylsuccinate synthetase

Question 16

adenylsuccinate –> AMP requires what two components and why is this significant

Answer 16

GTP and aspartate

helps regulate what purines are formed

Question 17

GMP –> GDP requires what two components and why is this significant

Answer 17

guanylate kinase, glutamate and ATP helps regulate what purines are formed

Question 18

adenosine deaminase inhibition or deficiency is related to what disease and causes what problem

Answer 18

SCID; build up of dATP which is very toxic and causes cell death

Question 19

AMP deaminase inhibition or deficiency is

Answer 19

asymptomatic

Question 20

allopurinol

Answer 20

inhibits xanthine oxidase which can treat gout because it inhibits uric acid formation

Question 21

nucleotides

Answer 21

GMP, AMP, IMP

Question 22

nucleosides

Answer 22

guanosine, inosine, adenosine, xanthine

Question 23

increased PRPP can lead to

Answer 23

hyperuricemia and increase likelihood of gout

Question 24

purine salvage (base –> nucleotide)

Answer 24

requires PRPP and PRT (phosphoribosyl transferase)

Question 25

guanine –> GMP

xanthine –> IMP

Answer 25

HGPRT and PRPP

Question 26

Adenine –> AMP

Answer 26

APRT and PRPP

Question 27

Lesch-Nyhan Syndrome

Answer 27

deficiency in HGPRT therefore increasing PRPP and can lead to gout

Question 28

Von Gierkes Disease

Answer 28

decreased glucose 6 phosphatase which shunts precursors to pentose phosphate pathway and increases purine metabolism and therefore increasing gout

Question 29

guanosine –> guanine enzyme

Answer 29

purine nucleoside phosphorylase

Question 30

deficiency in purine nucleoside phosphorylase

Answer 30

leads to increased dGTP and t-cell immunodeficiency

Question 31

chemotherapy

Answer 31

can lead to increased uric acid production and therefore increased gout