Abstract
An intracellular b-glucosidase (EC 3.2.1.21) from Aspergillus terreus NRRL 265 grown on whey permeate was purified to homogeneity as indicated by disc acrylamide gel electrophoresis with an apparent molecular mass of about 116 kDa. Optimal activity was observed at pH 5.0 and 60°C. The b- glucosidase had K m values of 2.5, 3.7 and 5.5 mM for p-nitrophenyl-β-D-glucopyranoside (p-NPG), cellobiose and salicin, respectively. Glucose and glucono-δ-lactone were found to be competitive inhibitors with apparent K i of 13.6 and 1.9 mM, respectively, when p-NPG was used as the substrate. Different metal cations had little or no effect on the enzyme activity, while Ag + and Hg 2+ had an inhibitory effect when used at high concentrations. In addition, b-glucosidase was found to be a glycoprotein containing 69% carbohydrate by weight and free from any myco-toxins. SH groups do not seem to play a role in the catalytic action of β-glucosidase as addition of iodoacetate, reduced glutathione or mercaptoethanol did not affect the activity. Key words : Aspergillus terreus , b-glucosidase, metal cations, iodoacetate.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
