gamma-Carboxyglutamic acid in human urine.
gamma-Carboxyglutamic acid, the amino acid responsible for the vitamin K dependent, Ca2+-binding structures of some of the blood coagulation proteins, has been identified in human urine. The amino acid wasisolated and its identity was proved by comparing it with synthetic gamma-carboxyglutamic acid by electrophoretic and chromatographic methods and by mass spectrometry. The isolated compound was also converted to glutamic acid by heat decarboxylation, a reaction consistent with its anticipated structure. A method for the quantitation of free gamma-carboxyglutamic acid in human urine was developed. The method consisted of an anion-exchange concentration step followed by automatic amino acid analysis using a pH 2.0 lithium citrate buffer. In three non-fasting adult males the urinary excretion of gamma-carboxyglutamic acid ranged between 27 and 42 mumol/24 h and in six non-fasting adult females it ranged between 19 and 32 mumol/24 h. One fasting adult male excreted 36 mumol/24 h.
D000328:Adult; D001322:Autoanalysis; D002849:Chromatography, Gas; D002852:Chromatography, Ion Exchange; D005260:Female; D005971:Glutamates / Q000302:isolation & purification / Q000652:urine*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008722:Methods; D009555:Ninhydrin; D014233:Tricarboxylic Acids / Q000652:urine
D005971:Glutamates; D014233:Tricarboxylic Acids; D009555:Ninhydrin