All nucleotides are _ in nature
Acidic
Synthesis of pyrimidines occurs in _
All enzymes are cytosolic except for _, in the _
- Liver
- DHO DH, mitochondria
CPS I is _
CPS II is _
- Catabolic
- Anabolic
CPSII, ATC, DHO part of _
CAD
_ is the starting point to all pyrimidines
UMP
RBC’s synthesize pyrimidines via _ from _
Uses enzyme _
- Salvage pathway, preformed bases
- Pyrimidine PRPP transferase
Degradation of cytosine > ?
Degradation of thymine > ?
- B-alanine > Acetate
- Amino butyric acid(marker for xray degradation)
T/F: All enzymes of purine synthesis are in the cytoplasm
False. Those for the salvage pathway aren’t
RDS of purine synthesis
Phosphoribosyl aminotransferase(PRA)
T/F: Active amide of Gln in PRA rxn needs ATP like all other active amide rxns.
False. Energy given by PP in PRPP
Carboxylation adds atom _(C or N)?
Does it require biotin like all other?
- C6
- No
Salvage purine synthesis in _, _
Uses _ > AMP
Uses _ > IMP
Uses _ > GMP
HGPRT abudant in _
- RBC, brain
- Adenine + PRPP
- Hypoxanthine + PRPP
- Guanine + PRPP
- Brain
Deficiency in HGPRT >
- Lesch-nyhan syndrome
- Self-mutilation
- Mental retard, hyperuricemia
- Cant salvage purines > uric acid
- More nt. synthesis > worsens
Hyperuricemia can result from (3)
Leads to
- Increase in purine catabolism(XO), Deficiency in HGPRT, Defect in G6Pase(VG)
- Gout/King’s disease
Enzyme reduces ribo-diphospho-nt > deoxyribo-phospho-nt
Enzyme oxidized at its expense
- Ribonucleotide reductase
- Thioredoxin reductase(NADPH)
Formation of TMP occurs only in _ via _
At the level of _
- DNA, thymidylate synthase
- Monophospho-nt
Donor of methyl for dTMP from dUMP is _
DHF > THF via?
- Hydroxymethyl THF(Methylene THF)…reduced to methyl
- DHF reductase
Overall activity site + ATP >?
Overall activity site + d-ATP >?
- RR active
- RR inactive
At substrate site:
ATP/d-ADP >
TTP/d-TTP >
d-GTP >
- dUDP, dCDP
- dGDP
- dADP
