CHARACTERIZATION OF THE SUBSITE STRUCTURE OF THE BETA-GLUCOSIDASE FROM ASPERGILLUS-NIGER, AN ASPECT OF THE MECHANISM OF CARBOHYDRATE-RECOGNITION

Steady-state kinetics on the reaction catalyzed by the beta-glucosidas e of Aspergillus niger were carried out to evaluate the kinetic parame ters, K-m, and k(o), for phenyl beta-D-glucosides. The k(o)/K-m values , which may relate to productive binding at subsites, were found to co rrelate with the substituent constant pi (hydrophobicity), suggesting that subsite 2 has a hydrophobic character. A ''hydrophobic-driven'' m echanism is considered to contribute to the productive E-S complex for recognition of the substrate. (C) 1998 Elsevier Science Ltd. All righ ts reserved.