ONPG [2-Nitrophenyl-β-D-Galactopyranoside], 1 G

ONPG is used in colormetric and spectrometric assays for the detection of galactosidase activity which are of interest in clinical, enviromental, food and molecular biology arenas. ONPG is hydrolysed by galactosidase to yield galactose and ortho-Nitrophenol, which is yellow in color and abosrbs light at 420 nm. The intensity of the color can be used to determine the rate at which galactosidase can hydrolyse lactose. The impact of experimental factors on the reproducibility of galactosidase assays has been reported.