Term
| purine ring is synthesized from: |
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Definition
| amino acids, tetrahydrofolate derivatives, CO2, requires 6 NTPs |
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Term
| glutamine-PRPP amidotransferase |
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Definition
| allosteric enzyme of de novo Purine synthesis, committed step in pathway, inhibited by AMP and GMP (products of pathway) |
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Term
| aspartate transcarbamoylase (ATCase) |
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Definition
| primary regulatory enxyme in de novo Pyrimidine biosynthesis, inhibited by CTP (end product of pathway) |
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Term
| purine synthesis (ring, reg. enzyme, regulation: where and by, requires) |
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Definition
ring synthesis: while attached to ribose
reg. enzyme: glutamine-PRPP amidotransferase
regulation: multiple sites
regulated by: AMP, GMP, IMP
requires: 6 NTPs (5 ATP, 1 ATP/GTP) |
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Term
| pyrimidine synthesis (ring, reg. enzyme, regulation: where and by, requires) |
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Definition
ring synthesis: before attached to ribose
reg. enzyme: ATCase
regulation: 1st step
regulated by: CTP
requires: 0-1 ATPs |
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Term
| deoxyribonucleotides are synthesized from: |
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Definition
| ribonucleoside Diphosphates |
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Term
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Definition
| enzyme that methylates dUMP into dTMP, target of drug 5-fluorouracil |
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Term
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Definition
| irreversible inhibitor of thymidylate synthase, attacks rapidly dividing cells (cancer) |
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Term
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Definition
| competitive inhibitor of dihydrofolate reductase, attacks rapidly dividing cells (cancer), structural analog of dihydrofolate |
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Term
| pyrimidine degradation yields: |
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Definition
| ammonia and succinyl-CoA (into CAC), increased urea synthesis |
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Term
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Definition
| uses adenosine deaminase, degraded into uric acid (excreted) |
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Term
| ADA (adenosine deaminase) deficiency/SCID (severe combined immunodeficiency disease) |
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Definition
| 100-fold increase in levels of dATP (leads to decrease in other nucleotides), B and Y lymphocytes not fully developed which leads to severe immunodeficiency, first successful gene therapy in 1990 |
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Term
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Definition
| deficiency in hypoxanthine-guanine phosphoribosyltransfrase (HGPT), leads to increased levels of PRPP and de novo purine biosynthesis (no purine salvage pathway), leads to CNS damage - retardation, compulsive self-mutilation behavior, only in male chilren |
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Term
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Definition
| PRPP+purine base -> purine ribonucleotide+PPi, adenine: requires denosine phosphoribosyl transferase, guanine: requires HGPT (hypoxanthine-guanine phosphoribosyl transferase) |
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Term
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Definition
| overproduction of uric acid (deficiency in purine metabolism), precipitation of sodium Urate crystals in joints and kidneys, treated with allopurinol (competitive inhibitor of xanthine oxidase) |
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