Studies on the Glycosidases in Jack Bean Meal

The monosaccharide u&s most commonly found in glycoproteins are n-galactose, n-mannose, M-acetyl-u-glucosamine, sialic acid, and L-fucose. The hydrolysis of individual carbohydrate units by specific glycosidases is an excellent tool for studying the sequenbial arrangement and anomeric configuration of the carbohydrate units in the glycoproteins. In previous studies, cr-mannosidase (cr-u-mannoside mannohydrolase, EC 3.2.1.24), /3-N-acetylglucosaminidase (P-2-acetylamino-2-dcoxy-n-glucoside acetylaminodeoxyglucohydrolnse, EC 3.2.1.30), and P-galactosidase (P-n-galactoside galactohydrolase, EC 3.2.1.23) were found to liberate mannose, N-acetylglucosamine, and galactose, respectively, from various glycoprotein preparations (l-3). Although the glycosidases which hydrolyze the carbohydrate portion of glycoproteins have been isolated from various sources (1, 2, 4-6), no convenient method is currently available for the simultaneous separation of several glycosidases from one source. Because of their promising applicability, we undertook an investigation to find a simple method for isolating individual glycosidase from jack bean meal without cross-contamination with other glycosidases. In this communicat~ion, we wish t.o describe the separation of cr-mannosidase, P-N-acetylglucosaminidase, and P-galactosidase simuhanrously from jack bean meal by an isoelectric focusing technique. Preparation of &zymes-Unless otherwise indicat’ed, all of the operations were conducted between 0” and 4”. A 100-g portion of jack bean meal (Sigma) was estract.ed by stirring vigorously