Nucleotide Metabolism Flashcards Preview

Biochemistry Post Midterm > Nucleotide Metabolism > Flashcards

Flashcards in Nucleotide Metabolism Deck (32):
1

what are the functions of nucleotides?

-building blocks of DNA and RNA
-carriers for activated intermediates
- components of CoA, FAD, NAD+ and NADP+

2

what is the structure of nucleotides?

-nitrogenous base
-pentose sugar
- phosphate groups

3

what is hypoxanthine?

base found in IMP - an intermediate in purine synthesis and degradation

4

what is xanthine?

found in xanthosine MP - intermediate in purine synthesis and degradation

5

what makes up a nucleoside?

N base + pentose sugar

6

What charge do the phosphate groups have?

negative charge

7

where does de novo purine synthesis take place?

cytoplasm of cell

8

what are the contributors to purine synthesis?

- aspartate
- glycine
-glutamine
-2 C from THF
- 1 CO2

9

what is the RLE and cmootied enzyme for purine synthesis?

glutamine phosphoribosyl pyrophosphate amidotransferase

10

what 2 enzymes do purine salvage require?

hypoxnthine-guanine phosphoribosyltransferase (HGPRT) and
adenine phosphoribosyltransferase (ARPT)

11

what are most purine degraded into?

uric acid

12

what 2 drugs treat gout?

colchicine
allopurinol

13

what activates glutamine PRPP amidotransferase?

glutamine and PRPP

14

what inhibits glutamine PRPP amidotransferase?

AMP, GMP, IMP

15

what do you need for all purine synthesis?

THF

16

what is the 1st purine made?

IMP

17

how much of nucleotides are degraded?

10% -- 90% are salvaged/recycled

18

what are the contributors for pyrimidine synthesis?

- aspartic acid
- glutamine
- CO2

19

what is the RLE in pyrimidine synthesis?

CPSII

20

where is CPSII?

cytoplasm

21

where does the N come from in CPSII and CPSI?

CPSI - ammonia
CPSII - glutamine

22

what activates CPSII?

ATP

23

what inhibits CPSII?

UTP

24

what is the only enzyme that converts ribo--> deoxyribo ?

ribonucleotide reductase

25

what does ribonucleotide reductase only work on?

diphosphate forms

26

how is orotic aciduria treated?

dietary uridine

27

what are the inhibitors of ribonucleotide reductase?

hydroxyurea
dATP

28

what are the 3 drugs we talked about that are used in chemotherapy?

methotrexate
hydroxyurea
5-fluorouracil

29

what is the only pyrimidine that requires THF?

thymidine

30

what is the target of methotrexate?

dihydrofolate reductase

31

what is the target of hydroxyurea?

ribonucleotide reductase

32

what is the target of 5-fluorouracil?

thymidylate synthetase