Nucleotide metabolism Flashcards Preview

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Flashcards in Nucleotide metabolism Deck (68):
1

nucleoside

linking a nitrogenous base to the 1' position of the ribose ring

2

nucletodie

nucleoside added to phosphate at 5' position of ribose ring

3

deoxyribonucleotide

hydroxyl group at 2' position of ribose ring is replaced with H

4

de novo synthesis

makeing nucleotide from scratch
takes a lot of energy

5

salavage pathways

generation of nucleotides from free bases and nucleosides from diet

6

first step in purine synthesis

PRPP generation

7

committed step of purine synthesis

amidophosphoribosyltransferase forming PRA from PRPP

8

what is the first purine syntheiszed

IMP

9

what is IMP a precusor for

synthesis of both AMP and GMP

10

how are carbon and/or nitrogen atoms donating to de novo pathway

amino acids

11

what provides carbon and oxygen to de novo pathway

CO2

12

what serves as a donor of one-carbon groups to de novo pathway

N10-formyl THF

13

what is the rate limiting enzyme of GMP synthase

IMP dehydrogenase

14

what inhibits IMP dehydrogenase

GMP

15

what is the rate limiting enzyme of AMP synthesis

adenylosuccinate synthase

16

what inhibits adenylosuccinate synthase

AMP

17

how do AMP and GMP get converted into ATP and GTP

nucleoside 5' monophosphate kinases and nucleoside 5'diphosphate kinases

18

what inhibits PRPPP synthetase

ADP and GDP

19

what is PRPP required for

synthesis of both purines and pyrimidines

20

what inhibits amidophosphoribosyltransferase

AMP and GMP

21

when is de novo purine synthesis limited

when purine nucleotides are abudent

22

incrase in PRPP do waht

stimulate de novo synthesis

23

what is the end product of purine metabolism

uric acid

24

how is uric acid excreted

kidney

25

hyperuricemia

excess uric acid in blood

26

what cause can reduced excretion of uric acid

renal insufficieny
metabolic acidosis

27

what can cause incrased production of uric acid

increased nucleotide turnover
diet rich in purine

28

how does EtOH affect uric acid

causes decreases excertion and increased production

29

is uric acid soluble or insoluble

insoluble

30

what is a possible consquence of increased uric acid

crystals of sodium urate deposite in joints, cause gouty arthritis

31

how do you treat hyperuricemia

allopurinol

32

how does allopurinol work

gets metabolized to oxypurinol which is a compoetitive inhibitor of xanthine oxidase

33

where does the synthesis of UMP take place

5 steps in cytoplasm, one in mitochondria

34

what is the first step in UMP synthesis

carbamoyl phosphate synthetase II

35

how do you get OMP to UMP

OMP decarbozylase

36

what are the first 3 steps of ump synthesis catalyzed by

CAD

37

what are teh last 2 steps of UMP synthase catalyzed by

UMP synthase

38

what causes orotic aciduria

defect in UMP synthase

39

symptoms of orotic aciduria

symptoms similiar to megaloblastic anemia

40

how do you treat orotic aciduria

pyrimidine supplementation

41

how do you get UTP to CTP

CTP synthase,

42

what does CTP use as a amino group donor

glutamine

43

how does UTP affect CTP synthase

as UTP levels increase, enzyme becomes more efficient at binding UTP

44

how does CTP affect CTP synthase

negative feedback

45

what catalyzes synthesis of deoxyribonucleutides

ribonucleotide reductase

46

what gets oxidized during ribonucleotide reductase

thioredoxin

47

wha tinhibits ribonucletodie reductase

hydroxyurea

48

what causes SCID

mutation in adenosine deaminase

49

do cells contain ribonucletodies of thymine

no

50

what catalyzes synthesis of dTMP

thymidylate syntahse

51

what happens when you inibt thymidylate synthase

prevent cell proliferation

52

inhibitor of thymidylate synthase

5-flurorourical

53

what happens when you degrate pyrimidine nucletodies

beta-amino acids

54

what is unique to thymine degration

beta-aminoisobutryate proudction

55

where does most de novo synthesis of nucleotides take palce

liver

56

what 2 enzymes do salavage of bases require

HGPRTase and APRTase

57

how do you get IMP in salaver pathway

hypoxanthine + PRPP

58

how do you get GMP in salvage pathway

Guanine + PRPP

59

how do you get AMP in salvage pathway

Adenine + PRPP

60

how does generation of IMP, GMP, and AMP by salvage pathways affect de novo synthesis

decreases it

61

what is lesch-nyhan syndrome caused by

deficeny of HGPRTase activity

62

symptoms of lesch-nyhan syndrome

hyperuricemia, uric acid stones, intellectual disablity, biting of fingers/lipis

63

what catalyzes pyrimidine bases and nucleosides

pyrimidine phosphoribosyltranserase

64

is cytosin salvaged in humans

no

65

what inhbiits CTP synthase

CTP

66

what inhbiits ribonucleotide reductase

NTPs and dNTPs

67

what inhbiits hypoxanthine guanine phosphoribosyltransferase

IMP and GMP

68

what inhibits adenine phosphoribosyltransferase

AMP