title: Coupled enzymatic assay for estimation of branched-chain L-amino acid aminotransferase activity with 2-Oxo acid substrates.
abstract: A convenient continuous spectrophotometric assay for estimation of branched-chain L-amino acid aminotransferase activity was established: Branched-chain 2-oxo acid-dependent transamination of L-glutamate was coupled-via 2-oxoglutarate-to L-aspartate aminotransferase plus L-malate dehydrogenase or to L-alanine aminotransferase plus L-lactate dehydrogenase as indicator systems. The rate of transamination can be monitored specifically by measuring the decrease in NADH absorbance at 334 nm over time. The method was applied, e.g., for evaluation of some kinetic properties of the rat heart (iso)enzyme.
authors.affiliation: Institut für Physiologische Chemie II, Heinrich-Heine-Universität Düsseldorf, Auf'm Hennekamp 65, Düsseldorf, D-40225, Federal Republic of Germany.
authors.forename: P
authors.initials: P
authors.lastname: Schadewaldt
authors.forename: F
authors.initials: F
authors.lastname: Adelmeyer
mesh_terms: D000818:Animals; D002417:Cattle; D002474:Cell-Free System / Q000201:enzymology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology; D045782:Hemiterpenes; D007527:Isoenzymes / Q000032:analysis; D007651:Keto Acids / Q000737:chemistry*; D016014:Linear Models; D008929:Mitochondria, Heart / Q000201:enzymology*; D051381:Rats; D013379:Substrate Specificity; D013696:Temperature; D000637:Transaminases / Q000032:analysis*
chemical_list: D045782:Hemiterpenes; D007527:Isoenzymes; D007651:Keto Acids; C016211:alpha-keto-beta-methylvaleric acid; C001505:alpha-ketoisovalerate; C013082:alpha-ketoisocaproic acid; D000637:Transaminases; C019798:branched-chain-amino-acid transaminase