Nucleotide Metabolism Flashcards
what are the functions of nucleotides?
- building blocks of DNA and RNA
- carriers for activated intermediates
- components of CoA, FAD, NAD+ and NADP+
what is the structure of nucleotides?
- nitrogenous base
- pentose sugar
- phosphate groups
what is hypoxanthine?
base found in IMP - an intermediate in purine synthesis and degradation
what is xanthine?
found in xanthosine MP - intermediate in purine synthesis and degradation
what makes up a nucleoside?
N base + pentose sugar
What charge do the phosphate groups have?
negative charge
where does de novo purine synthesis take place?
cytoplasm of cell
what are the contributors to purine synthesis?
- aspartate
- glycine
- glutamine
- 2 C from THF
- 1 CO2
what is the RLE and cmootied enzyme for purine synthesis?
glutamine phosphoribosyl pyrophosphate amidotransferase
what 2 enzymes do purine salvage require?
hypoxnthine-guanine phosphoribosyltransferase (HGPRT) and adenine phosphoribosyltransferase (ARPT)
what are most purine degraded into?
uric acid
what 2 drugs treat gout?
colchicine
allopurinol
what activates glutamine PRPP amidotransferase?
glutamine and PRPP
what inhibits glutamine PRPP amidotransferase?
AMP, GMP, IMP
what do you need for all purine synthesis?
THF
what is the 1st purine made?
IMP
how much of nucleotides are degraded?
10% – 90% are salvaged/recycled
what are the contributors for pyrimidine synthesis?
- aspartic acid
- glutamine
- CO2
what is the RLE in pyrimidine synthesis?
CPSII
where is CPSII?
cytoplasm
where does the N come from in CPSII and CPSI?
CPSI - ammonia
CPSII - glutamine
what activates CPSII?
ATP
what inhibits CPSII?
UTP
what is the only enzyme that converts ribo–> deoxyribo ?
ribonucleotide reductase
