The determination of precursors to urinary methyl-malonic acid in man; measurement of urinary excretion and specific activity
1969; Elsevier BV; Volume: 23; Issue: 2 Linguagem: Inglês
10.1016/0009-8981(69)90042-4
ISSN1873-3492
AutoresJoseph A. DeGrazia, Mathews B. Fish, Myron Pollycove, Michael Ponnamperuma,
Tópico(s)Amino Acid Enzymes and Metabolism
ResumoA method is described for the determination of urinary methylmalonic acid and its specific activity following the administration of 14C-labeled precursors to humans. The method involves ether extraction, anion exchange column chromatography and colorimetric determination of the separated methylmalonic acid, after coupling to diazotized p-nitroaniline. Specific activity determination includes liquid scintillation quantitation of the 14C content after further purification of the methyl-malonic acid fraction by thin-layer chromatography. Analytical losses were corrected for by use of 3H-labelled methylmalonic acid. Day to day analytical variance and recovery data are presented. Increased methylmalonic acid urinary excretion was noted in all vitamin B12-deficient subjects. While there was 14C incorporation into urinary methylmalonic acid after intravenous administration of [2−14C] propionate in both a normal subject and in a vitamin B12-deficient patient, a much larger fraction of the injected dose appeared in the urinary methylmalonic acid of the vitamin B12-deficient patient.
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