Metabolism and transport of gamma-carboxyglutamic acid.
gamma-Carboxyglutamic acid residues have beeh shown to be present in prothrombin, the other vitamin K-dependent clotting factors, and more recently in bone and kidney proteins. This amino acid is formed by a posttranslational vitamin K-dependent carboxylation of glutamyl residues in polypeptide precursors of these protens. It has now been demonstrated that this amino acid, either in the free or peptide-bound form, is not metabolically degraded by the rat, but is quantitatively excreted in the urine. In nephrectomized rats, the tissue concentration of intravenously administered gamma-carboxyglutamic acid is increased, but there is still no evidence of any oxidative metabolism of this amino acid. These amino acid is transported by kidney slices against a concentration gradient, but does not accumulate in liver, intestinal or brain tissues. Preliminary data suggest that gamma-carboxyglutamic acid may be concentrated by a carrier system different from that utilized by other amino acids.
D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D009392:Nephrectomy; D051381:Rats; D014233:Tricarboxylic Acids / Q000378:metabolism
D000621:Aminoisobutyric Acids; D005971:Glutamates; D014233:Tricarboxylic Acids