Nucleotides

Front 1

adenine numbering

Back 1

Front 2

Back 2

adenine

Front 3

Back 3

adenosine 5'-diphosphate (ADP)

Front 4

Back 4

adenosine 5'-monophosphate (AMP)

Front 5

Back 5

adenosine 5'-triphosphate (ATP)

Front 6

Back 6

adenosine

Front 7

Back 7

cytosine

Front 8

Back 8

cytidine

Front 9

Back 9

deoxyadenosine 5'-monophosphate (dAMP)

Front 10

Back 10

deoxyadenosine

Front 11

Back 11

guanine

Front 12

Back 12

hypoxanthine

Front 13

Back 13

thymidine

Front 14

Back 14

thymine

Front 15

uracil numbering

Back 15

Front 16

Back 16

uracil

Front 17

Back 17

uridine

Front 18

Back 18

xanthine

Front 19

bases and nucleosides can readily cross most cell membranes, but nucleotides and deoxynucleotides are trapped by this

Back 19

negative charge of phosphate group(s)

Front 20

concentration of ribonucleotides

Back 20

millimolar

Front 21

concentration of deoxyribonucleotides

Back 21

micromolar

Front 22

predominant form of nucleotides and deoxynucleotides in cells

Back 22

triphosphate (>70%)

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cytosine and thymine are derived form this

Back 23

uracil

Front 24

in purine synthesis:
base - ?
nucleoside - ?
nucleotide - ?

Back 24

base - hypoxanthine
nucleoside - inosine
nucleotide - inosinate/inosine-5'MP (IMP)

Front 25

building purine ring requires ___ ATP

Back 25

7

Front 26

step 1 of purine synthesis: synthesis of PRPP
___ (produced by ___) --> PRPP
catalyzed by ___

Back 26

ribose-5-phosphate (produced by pentose shunt pathway) --> PRPP
catalyzed by PRPP synthase

Front 27

regulates PRPP synthase

Back 27

(+) Pi
(-) ADP
also...
(-) AMP
(-) GDP

Front 28

step 2 of purine synthesis: synthesis of PRA
___ atom added
catalyzed by ___

Back 28

step 2 of purine synthesis: synthesis of PRA
N9 atom added
catalyzed by glutamine PRPP amidotransferase

Front 29

most important regulatory step in purine synthesis

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synthesis of PRA (step 2 adding N9)

Front 30

regulates glutamine PRPP amidotransferase

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(+) PRPP
(-) IMP
(-) AMP
(-) GMP
(one site binds IMP and GMP, other binds AMP)

Front 31

step 4 of purine synthesis: ___ deliver C8
catalyzed by ___

Back 31

N10-formal-tetrahydrofolate delivers C8

transformylase activity

Front 32

step 6 of purine synthesis: closure of ___ ring

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imidazole ring

Front 33

only part of aspartate that is retained in purine synthesis

(rest cleaved off as ___)

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N1

(fumarate)

Front 34

fumarate can be used in this

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tricarboxylic cycle

Front 35

step 10 of purine synthesis: ___ delivers C2
catalyzed by ___

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N10-formyl-tetrahydrofolate delivers C2

transformylase activity

Front 36

1st step in branched pathway for synthesis of AMP or GMP:
- ___ to form XMP (to become GMP)
catalyzed by ___
regulated by ___

OR

- ___ to form adenylosuccinate (to become AMP)
catalyzed by ___
regulated by ___

Back 36

- oxidation of C2 to form XMP (to become GMP)
catalyzed by IMP dehydrogenase
regulated by GMP (-)

OR

- substitution of Asp for C=O to form adenylosuccinate (to become AMP)
catalyzed by adenylosuccinate synthetase
regulated by AMP (-), GTP (+)

Front 37

2nd step in branched pathway for synthesis of AMP or GMP:
-substitution of ___ to form GMP (brought in by ___)
catalyzed by ___
regulated by ___

OR

-removal of ___ to form AMP
catalyzed by ___

Back 37

-substitution of C-NH2 for C=O to form GMP (brought in by glutamine)
catalyzed by GMP synthetase
regulated by ATP (+)

OR

-removal of fumarate to form AMP
catalyzed by adenylosuccinase

Front 38

performed with purines to increase TCA intermediate under stress

Back 38

AMP --> IMP --> AMP + fumarate
(just for the purpose of removing fumarate)

Front 39

deficiency of ___ leads to muscle cramps during exercise

Back 39

AMP deaminase (can't make IMP to convert back to AMP to release fumarate)

Front 40

in purine nucleotide degeneration, nucleotides lose ___ then lose ___

Back 40

PO4 then ribose

Front 41

purine nucleotide degeneration is catalyzed by ___

Back 41

xanthine dehydrogenase/xanthine oxidase

Front 42

final produce of purine nucleotide degeneration

Back 42

uric acid

Front 43

may cause gout if it precipitates in joints

Back 43

uric acid (final produce of purine degeneration)

Front 44

inhibits xanthine oxidase to prevent gout

Back 44

allopurinol

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Front 46

order of pieces added

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Front 47

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Front 48

order of pieces added

Back 48

Front 49

cause of gout:
___ --> increased glucose-6-PO4 --> pentose shunt flux --> increased R-5-P --> ___

Back 49

beta glucose-6-phosphatase
PRPP

Front 50

cause of gout:
elevated level of this enzyme

Back 50

PRPP synthetase

Front 51

cause of gout:
loss of feedback inhibition of ___ by ___

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glutamine PRPP amidotransferase by AMP, GMP and IMP

Front 52

cause of gout:
decreased ___ --> increased PRPP --> increased ___

Back 52

decreased HGPRT
increased purine biosynthesis

Front 53

sex-linked gene on x chromsome leading to men getting more gout than women if mutated

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HGPRT

Front 54

partial decreased in HGPRT --> ___
severe decreased or lack of HGPRT --> ___

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gout
lesch-nyhan syndrome

Front 55

added last in pyrimidine synthesis

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ribose

Front 56

pyrimidine synthesis:
base - ?
nucleoside - ?
nucleotide - ?

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base - uracil
nucleoside - uridine
nucleotide - uridylate (UMP)

Front 57

cofactor used only for dTMP synthesis

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folate cofactor

Front 58

3 parts of trifunctional enzyme in pyrimidine synthesis

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(CAD)
CPS II
ACTase
Dihydroorotase

Front 59

principal regulatory site in pyrimidine synthesis

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CPS II

Front 60

step 1 of pyrimidine synthesis: carbamoyl phosphate
(synthesized from ___ and ___)
catalyzed by ___

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glutamine and CO2
catalyzed by CPS II

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regulates CPS II

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(+) ATP
(+) PRPP
(-) UTP

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step 2 of pyrimidine synthesis: addition of aspartate
catalyzed by ___

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ACTase

Front 63

regulates ACTase

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(+) ATP
(-) CTP
ONLY IN BACTERIA!

Front 64

regulated only in bacteria

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ACTase

Front 65

step 3 of pyrimidine synthesis: ring closure
catalyzed by ___

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dihydroorotase

Front 66

step 4 of pyrimidine synthesis: ring oxidation (C=C)
catalyzed by ___
uses ___ as proximal cofactor and ___ as ultimate electron acceptor
reaction takes place in ___

Back 66

catalyzed by dihydroorotate dehydrogenase
uses NAD+ as proximal cofactor and coenzyme Q as ultimate electron acceptor
reaction takes place in mitochondria

Front 67

reaction that occurs in mitochondria

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pyrimidine ring oxidation

Front 68

step 5 of pyrimidine synthesis: addition of ribose
forms ___
catalyzed by ___
uses ___ as an activated substrate
reactions takes place in ___

Back 68

forms OMP
catalyzed by ORPTase
uses PRPP as an activated substrate
reactions takes place in cytosol

Front 69

deficiency of either of these 2 enzymes causes orotic aciduria

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ORPTase
OMP decarboxylase

Front 70

step 6 of pyrimidine synthesis: removal of COO- at C6
forms ___
catalyzed by ___
regulated by

Back 70

forms UMP
catalyzed OMP decarboxylase
regulated by UMP (-)

Front 71

synthesis of CTP from UMP:
-first UMP --> ___
-use ___ and ___ to replace carbonyl with ___
-catalyzed by ___
-regulated by ___

Back 71

-first UMP --> UDP --> UTP
-use ATP and glutamine to replace carbonyl with amino acid
-catalyzed by CTP synthetase
-regulated by CTP (-)

Front 72

synthesis of dTMP from UMP:
-requires folate cofactor - ___ which adds ___ to ___
- H4-folate is ___ to H2-folate in the process
(must use ___ to go back, H2-->H4)

Back 72

-requires folate cofactor - N5N10-methylene H4-folate which adds -CH3 to C5
- H4-folate is reduced to H2-folate
(must use dihydrofolate reductase to go back, H2-->H4)

Front 73

first 3 steps of pyrimidine degradation and enzymes involved

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dephosphorylation
deamination (cytidine deaminase... cytidine --> uridine)
deribosylation (phosphorylase... uridine --> uracil)

Front 74

key irreversible step of pyrimidine degradation and its catalyst

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reduction of ring (double bond to single bond)
catalyzed by dihydrouracil dehydrogenase

Front 75

ribonucleotide reductase reaction:
-used for creating ___
-ribose ___ is reduced to ___
-reducing source is ___
-intermediate carrier is ___ or ___
-substrate must be at ___ level

Back 75

-used for creating deoxynucleotides
-ribose 2'-OH is reduced to 2'-H
-reducing source is NADPH
-intermediate carrier is thioredoxin or glutaredoxin
-substrate must be at diphosphate level (NDP--> dNDP)

Front 76

regulates ribonucleotide reductase

Back 76

(-) high dTTP
(-) high dATP