Assay of gamma-glutamyltransferase with amino acid dehydrogenases from Bacillus stearothermophilus as auxiliary enzymes.
A spectrophotometric assay for serum gamma-glutamyltransferase (gamma-GT, EC 2.3.2.2) based on the increasing absorbance at 340 nm due to NADH formation is described. Using gamma-glutamyl dipeptides as the donor substrate, amino acids formed by the gamma-glutamyl transfer from the donor substrate to the acceptor substrate glycylglycine are stoichiometrically converted by the corresponding amino acid dehydrogenases from Bacillus stearothermophilus to produce their keto acids and NADH. gamma-Glutamylalanine was found to be the most specific and sensitive donor substrate. The method can be mechanized, is free of interference and correlates well with conventional methods.
Research and Development Center, UNITIKA Ltd., Kyoto, Japan.
H
H
Kondo
M
M
Hashimoto
K
K
Nagata
K
K
Tomita
H
H
Tsubota
D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D007202:Indicators and Reagents / Q000592:standards; D013056:Spectrophotometry, Ultraviolet; D005723:gamma-Glutamyltransferase / Q000097:blood* / Q000378:metabolism
D007202:Indicators and Reagents; D000594:Amino Acid Oxidoreductases; D005723:gamma-Glutamyltransferase