Hydrolytic and transglucosylation activities of a purified calf spleen β-glucosidase

Abstract

Certain properties of the transglucosylitic activity and the hydrolytic activity of a purified calf spleen β-glucosidase (β- d-glucoside glucohydrolase EC 3.2.1.21) were investigated. There was a stimulation of both activities by sodium taurocholate and “Gaucher's factor”. The K m values for 4-methylumbelliferyl-β- d-glucoside and glucosylceramide as donors in the transglucosylation reaction were 2 mM and 0.075 mM, respectively. The K m for ceramide as acceptor was 0.149 mM with both of these compounds. The ability of several glucoside to act as donors was examined. The capacity of catalyze this “transglucosylation” reaction is greatly diminished in spleen tissue samples from Gaucher's patients. The enzyme possesses the capacity to hydrolyze 4-methylumbelliferyl-β- d-glucoside, p- nitrophenyl-β- d-glucoside , glucosylsphingosine, glucosylceramide and deoxycorticosterol-β- d-glucoside. It is postulated that a single enzyme protein may be responsible for both the hydrolytic and the transglucosylitic activities.