Purification et propriétés de deux (1 → 4)-β-d-glucosidases d'Aspergillus roseus

Abstract Two constitutive (1 → 4)-β- d -glucosidases from Aspergillus roseus were highly purified (275- and 1059-fold) on DEAE-Sepharose and hydroxyapatite columns. Electrophoresis on poly(acrylamide) gels showed for each enzyme, a single protein band containing an enzymic activity that hydrolyses 4-nitrophenyl β- d -glucopyranoside and cellulose. Classical cellulose hydrolysis was obtained by the combined action of three proteins, an endocellulase, an exocellulase, and a β- d -glucosidase. In the case of A. roseus , the purified β- d -glucosidases are able to hydrolyze the cellulose substrate giving d -glucose as the only end product. Physico-chemical features of these glycosylated enzymes such as optimum pH, molecular weight, K m , and substrate specificity were determined.