Hydrolysis of Aryl β-D-Glucofuranoside by Almond Emulsin β-Glucosidase

Abstract

[beta]-D-Glucofuranosides of 2-naphthol, phenol, guaiacol and m-cresol were hydrolyzed by almond emulsin, and the hydrolysis was inhibited by glucono-l,4-lactone and glucono-l,5-lactone. The kinetics of the hydrolysis of aryl [BETA]-D-glucofuranoside by almond emulsin [beta]-glucosidase was investigated. The pH optimum of the [beta]-D-glucofuranoside is between 5.0 and 5.25 in phosphate-citrate buffer at 30[degree]. The Michaelis-Menten constant is: 2-naphthyl [beta]-D-glucofuranoside, 2.0 x 10-3 [image]; phenyl [beta]-D-glucofuranoside, 6.2 x 10-2 M; guaiacol [beta]-D-glucofuranoside, 5.5 x lO-2 [image]; m-cresyl [beta]-D-glucofuranoside, 5.0 x 10-2 [image]. The kinetics of The hydrolysis of the corresponding glucopyranoside by the enzyme was also investigated. The pH optimum is approximately the same as furanoside. The Michaelis-Menten constant is: 2-naphthyl [BETA]-D-glucopyranoside, 1.4 x 103 [image]; phenyl [beta]-D-glucopyranoside, 4.0 x 10-2 [image]; guaiacol [beta]-D-glucopyranoside, 3.2 x 102 [image]; m-cresyl [beta]-D-glucopyranoside, 2.2 x 10-2 m. [beta]-D-glucofuranoside could be a substrate for almond emulsin [beta]-glucosidase.