title: Branched-chain-amino-acid aminotransferase assay using radioisotopes.
abstract: A method for the assay of the activity of branched-chain-amino-acid aminotransferase from Escherichia coli has been developed. Radioactive isoleucine is used, the radioactive oxoacid formed in the enzymic reaction is converted to its p-nitrophenylhydrazone, and the hydrazone is extracted into toluene based scintillation liquid. The small reaction tubes containing the toluene layer and the reaction mixture as a water layer are placed into liquid scintillation vials and counted for radioactivity. The radioactive amino acid remaining in the water layer causes only a rather low background.
authors.affiliation: Department of Biochemistry, University of Turku, Finland.
authors.forename: R K
authors.initials: RK
authors.lastname: Airas
mesh_terms: D002250:Carbon Radioisotopes; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D011865:Radioisotope Dilution Technique; D012588:Scintillation Counting; D000637:Transaminases / Q000032:analysis* / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D000637:Transaminases; C019798:branched-chain-amino-acid transaminase