A Highly Sensitive Bioluminescent Assay of β-D-Galactosidase fromEscherichia coliUsing 2-Nitrophenyl-β-D-galactopyranoside as a Substrate

Publisher Website
Google Scholar
Abstract
A highly sensitive bioluminescent assay of β-D-galactosidase from Escherichia coli is described. D-Galactose was released from 2-nitrophenyl-β-D-galactopyranoside as a substrate by the catalytic action of β-D-galactosidase, and subsequently NADH was formed using galactose dehydrogenase. NADH was measured by a bioluminescent assay using NAD(P)H:FMN oxidoreductase and luciferase from Photobacterium fischeri. The detection limits of β-D-galactosidase for 100 and 1,000 min assays were 2 × 10−21 mol and 2 × 10−22 mol, respectively. When the volume of the reaction mixture for β-D-galactosidase assay was reduced from 2 μ to 0.5 μ1, the detection limits were reduced to half.