Nucleotide Metabolism Flashcards Preview

Biochemistry Post Midterm > Nucleotide Metabolism > Flashcards

Flashcards in Nucleotide Metabolism Deck (32)
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1
Q

what are the functions of nucleotides?

A
  • building blocks of DNA and RNA
  • carriers for activated intermediates
  • components of CoA, FAD, NAD+ and NADP+
2
Q

what is the structure of nucleotides?

A
  • nitrogenous base
  • pentose sugar
  • phosphate groups
3
Q

what is hypoxanthine?

A

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

4
Q

what is xanthine?

A

found in xanthosine MP - intermediate in purine synthesis and degradation

5
Q

what makes up a nucleoside?

A

N base + pentose sugar

6
Q

What charge do the phosphate groups have?

A

negative charge

7
Q

where does de novo purine synthesis take place?

A

cytoplasm of cell

8
Q

what are the contributors to purine synthesis?

A
  • aspartate
  • glycine
  • glutamine
  • 2 C from THF
  • 1 CO2
9
Q

what is the RLE and cmootied enzyme for purine synthesis?

A

glutamine phosphoribosyl pyrophosphate amidotransferase

10
Q

what 2 enzymes do purine salvage require?

A
hypoxnthine-guanine phosphoribosyltransferase (HGPRT) and
adenine phosphoribosyltransferase (ARPT)
11
Q

what are most purine degraded into?

A

uric acid

12
Q

what 2 drugs treat gout?

A

colchicine

allopurinol

13
Q

what activates glutamine PRPP amidotransferase?

A

glutamine and PRPP

14
Q

what inhibits glutamine PRPP amidotransferase?

A

AMP, GMP, IMP

15
Q

what do you need for all purine synthesis?

A

THF

16
Q

what is the 1st purine made?

A

IMP

17
Q

how much of nucleotides are degraded?

A

10% – 90% are salvaged/recycled

18
Q

what are the contributors for pyrimidine synthesis?

A
  • aspartic acid
  • glutamine
  • CO2
19
Q

what is the RLE in pyrimidine synthesis?

A

CPSII

20
Q

where is CPSII?

A

cytoplasm

21
Q

where does the N come from in CPSII and CPSI?

A

CPSI - ammonia

CPSII - glutamine

22
Q

what activates CPSII?

A

ATP

23
Q

what inhibits CPSII?

A

UTP

24
Q

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

A

ribonucleotide reductase

25
Q

what does ribonucleotide reductase only work on?

A

diphosphate forms

26
Q

how is orotic aciduria treated?

A

dietary uridine

27
Q

what are the inhibitors of ribonucleotide reductase?

A

hydroxyurea

dATP

28
Q

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

A

methotrexate
hydroxyurea
5-fluorouracil

29
Q

what is the only pyrimidine that requires THF?

A

thymidine

30
Q

what is the target of methotrexate?

A

dihydrofolate reductase

31
Q

what is the target of hydroxyurea?

A

ribonucleotide reductase

32
Q

what is the target of 5-fluorouracil?

A

thymidylate synthetase