title: A spectrophotometric method for the determination of gamma-glutamyl cyclotransferase with alanine dehydrogenase in the presence of anthglutin.
abstract: gamma-Glutamyl cyclotransferase activity is assayed in tissues by a colorimetric method using gamma-glutamyl alanine as a substrate coupled with alanine dehydrogenase from B. sphericus, to measure the formation of NADH. In order to avoid interference by the reaction catalyzed by gamma-glutamyl transpeptidase, anthglutin, a specific inhibitor of the transpeptidase was included in the reaction mixture. The Km value of rat kidney gamma-glutamyl cyclotransferase with respect to gamma-glutamyl alanine appeared to be the same when determined by either the colorimetric or the radiometric method. This assay presents a reliable alternative to the use of radiolabeled substrate and is used for the assay of gamma-glutamyl cyclotransferase in a variety of physiological and experimental samples.
mesh_terms: D000217:Acyltransferases / Q000032:analysis*; D000409:Alanine / Q000032:analysis; D050788:Alanine Dehydrogenase; D000594:Amino Acid Oxidoreductases; D000818:Animals; D002021:Buffers; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005971:Glutamates / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000201:enzymology; D011247:Pregnancy; D051381:Rats; D013997:Time Factors; D005722:gamma-Glutamylcyclotransferase / Q000032:analysis*; D005723:gamma-Glutamyltransferase / Q000037:antagonists & inhibitors*
chemical_list: D002021:Buffers; D005971:Glutamates; D000594:Amino Acid Oxidoreductases; D050788:Alanine Dehydrogenase; D000217:Acyltransferases; D005723:gamma-Glutamyltransferase; D005722:gamma-Glutamylcyclotransferase; C018830:anthglutin; D000409:Alanine