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28 Cards in this Set
- Front
- Back
Purine and Pyr
what bond links the base and sugar together in a Nt? Sam donates what? PAPS donates what |
bond - N-glycosidic link
Sam - methyl PAPS - a sulfate donor |
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PUR and PYR
IMP - whats the base What does thioredoxin do? |
Base - H
Thioredoxin - co-enz reduces ribonucleotide reductase, an electron donor is reduced by NADPH in thioredoxin reductase |
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IMP-->AMP
requires? inhibited by? IMP-->GMP requires? inhibited by? |
imp-->AMP requires GTP inhibited by AMP
IMP-->GMP first step (IMP->XMP) inhibited by GMP second step (XMP->GMP) requires ATP |
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How do you get from amp to imp? gmp to imp?
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amp to imp - amp deaminase
gmp to imp - gmp reductase |
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Ribonucleotide reductase
two regulatory sites how is it regulated What pharmacological drug acan inhibit ribonucleotide reductase? |
REgulator sites
1) activity site( + ATP, -dATP/dGTP) 2) specificity site - needs a spec allosteric positive affector (dTTP) Hydroxyurea |
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PUR and Pyr
ADA deficiency what doeas ADA normally do? Leads to higher levels of what molecule and subsequent inhibition of what? CLinical manifestation? |
Adenosine deaminase deficiency - normally converts adenosine to inosine the catabolism of purines, inherited disorder, leads to higher dATP which then inhibits ribonucleotide reductase,
Clinical - SCIDS both t and b cells, 20% of these types of syndromes are from ADA deficiency |
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PR/PY
draw the catabolism of the purines amp and gmp |
amp-->adenosine (nucleotidase)
adenosine -->inosine (ADA) inosine--> hypoxanthine (PNP) hypoxanthine --> Xanthine(XO) GMP--> guanosine (nucleotidase) guanosine-->Guanine (PNP) guanine-->xanthine(guanase) |
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in what order are ring C and N's added in purine
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Glutamine [n]
glycine[c/n](ATP) N10-H4-F[c] Glutamine[n] (ATP mg2+ Ring closure (atp mg2+) CO2[c] Asp[n] (ATP) N10-H4-F[c] Ring Closure |
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draw Pyrimidine synthesis
pg 106, remember CAD and UMP synthase what is the committed step? |
good luck
commited - synthesis of carbamoyl aspartate by aspartate transcarbamoylase |
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What are the main reactios of the salvage pathway?
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Phosphoribosylate purine bases (APRT/HGPRT)pg 103
H or G --> IMP or GMP Phorphorylate nucleosides(ie adenosine --> amp via adenosine kinase) |
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in what order are ring C and N's added in a pyrimidine?
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glutamine and CO2 (ATP)
Aspartic acid ring closure ALL HAPPEN IN CAD |
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adenosine --> inosine via what enz
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adenosine deaminase
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PU an PYR
how do you go from OMP to UMP? from utp to ctp? dUMP can arise from what two molecules? |
omp to ump - orotidylic acid decarboxylate
utp to ctp - aminate using CTP Sythetase dUMP - dUDP and dCMP |
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PRPP glutamyl amidotransferase
Purine/Pyrimidine anabolism/catabolism |
Purine Anabolism
adds glutamine to PRPP COMMITTED/REGULATED +PRPP -end products |
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PUR/PYR
what inhibits thymidylate synthase |
Thymidylate synthase takes dUMP to TMP, 5-fluorouracil a Thymine analog inhibits thymidylate synthase,
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PUR.PYR
nucleic acids are degraded to Nt's by? how are Nt's degraded to nucleosides? how are Nucleosides degraded to R-1-P? |
degredation - via nucleases
Degradation - via nucleotidases Degradation - via nucleoside phosphorylase |
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inosine --> hypoxanthine
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Purine Nucleoside Phosphorylase
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How does salvage inhibit de novo synthesis?
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decreases PRPP, and generates nucleoside monophosphates that inhibit PRPP glutamyl amidotransferase
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What does Carbamoyl phosphate synthetase II do?
CPSII |
first step in pyrimidine catabolism, co2/glutamine -->CAP
REGULATED |
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Guanosine-->Guanine
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Purine Nucleoside Phosphorylase
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what does aspartate transcarbamoylase do?
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second step in pyrimidine catabolism
CAP-->CAA COMMITTED |
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PY and P
describe the use of allopurinol |
HX analog, competetive inhibitor of xanthine oxidase ( part of the pur catabolic pathway resulting in uric acid), increases hypo and xanthine levels , at the active site allopurinal is oxidized to oxypurinol, oxypurinol is not readily freed from the active site, sequestering XO, the oxypurinol that IS released is salvaged to a Nt that inhibits amidotransferase (PRPP glutamyl) thus inhibiting de novo sythesis so you cant make more to degrade
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PUR/PYR
Hereditary orotic aciduria deficiency of what two reactions/ what enzyme CLINICAL sypmtoms treatment |
aciduria - inherited, pyr de novo synthesis, orotate decarboxylase and orotate phosphoribosyl transferase (UMP SYNTHASE) are deficient, increase OA excretion and [],
CLINICAL - failure to develop, anemia TREATMENT - large amounts of uridine |
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PUR/PYR
Lesch-Nyhan syndrome deficiency of? results in high [] of ? Clinical signs? |
inherited x-linked,
Absent HGPRT activity High [] of PRPP and therefore uric acid Clinical syptoms - hyperuricemia w/gout, self-mutilation, aggressive, developmental delay, low motor skills, usuall die of renal failure |
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what does CTP synthetase do?
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converts utp--> CTP in pyrimidine anabolism, uses glutamine and atp
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PyR and PUR
PYR catabolism, how do you go from cytosine to uracil? What can you detect in urine to measure DNA turnover? |
cyt- ura: deamination
beta-aminoisobutyrate, a unique degradation product of thymine |
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describe the process of going from dUMP -->TMP
is it pur/pyr catabolism/anabolism? |
pyr anabolism
methylate the dUMP using THF THF is oxidized to DHF DHF is regenerated by DHF reductase (coENZ NADPH) ser-->glu adds the 1C group to THF Methotrexate inhibits DHF reductase |
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PUR.PYR
Acyclovir |
a modified guanosine, HIV and HSV herpes , inhibits replication, along with AZT
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