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 Q Orotic acid  



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Author5 Posts
  #1

this forum seems dead! but my bio questions push me to post maybe some day some one some how knows the answers and cares to sharewink

a UW Q;patient 14 months yearold with high urine orotic acid and megaloblastic anemia ,,GIVING which one of these supplements would most likely benefits him?

1.folic acid

2.iron.

3.vitc

4.uridine

answer;

uridine,,,problem is in metabolism of orotic acid ,by giving uridine we make UMP -pyrimidine salvage-and UMP is an inhibitor of carbamoylphosphate synthase 2 so now less orotic acid is made.

my question ;why not folic acid?

nor kaplan neither FA talk about pyrimidine salvage pathways but i have seen 2 q on these,in UW! R THEY REALY IMPORTANT FOR EXAM??




  #2

This is on FA 2010 page 68 of Bichemestry section


  #3

oh my god


  #4

grin4- URIDINE WILL CAUSE NEGATIVE FEEDBACK TO CARBOMYL SYNTHASE SO NO MORE OROTIC WILL SYNTHSIZED,,THIS IS 1ST,,,,,,,,,,,,THE 2ND is uridine will continue steps of pathway distal to orotic steps,,,,,,thanks


  #5

First of all I want to say that the question is incomplete because it does not tell about hyperammonemia or BUN values so as to differentiate very imp. enzyme deficiencies.i.e. OTC(liver mitochondria) or 2 enzymes used in pyramidine synthesis.smiling face

I do agree with mohammen.
I WANT TO ADD THAT FOLATE IS REQUIRED IN dTMP synthesis in denovo Pyramidine synthesis.

Any more info is very welcome

Thanks.grin





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