A rapid and continuous spectrophotometric method to measure beta-glucosidase activity based on p-nitrophenyl beta-O-D-glucopyranoside hydrolysis

An improved p-nitrophenyl-beta-O-D-glucopyranoside method to measure beta-g lucosidase (EC, 3.2.1.21) activity is presented in which a cyclodextrin is added to the enzymatic mixtures. The inclusion complex consisting of p-nitr ophenol and alpha-cyclodextrin has a higher epsilon than p-nitrophenol alon e, thus increasing the sensitivity of the original method. The proposed met hod makes it possible continuously to record the formation of the reaction product and, since it is possible to measure the initial reaction rates, th e method is suitable for kinetic studies. Copyright (C) 1999 John Wiley & S ons, Ltd.