Isolation and some properties of two extracellular β‐glucosidases from Trichosporon adeninovorans

Abstract

The yeast Trichosporon adeninovorans secretes two multiple forms of β‐glucosidase at a high rate if grown in a medium containing cellobiose. Following mutagenesis a mutant strain resistant to 2‐deoxy‐D‐glucose was selected. This strain produced more β‐glucosidase activity and had acquired a strong resistance against repression by glucose. The β‐glucosidases were separated one from each other by chromatography on hydroxylapatite and by gel filtration. Both enzymes have similar properties. The optimal temperature for their activity was 60 to 63°C and the enzymes displayed highest activity at pH of 4.5. The molecular weight of β‐glucosidase I was found to be 570,000 and that for β‐glucosidase II was 525,000. The Km value for cellobiose was determined to be 4.1 mM for β‐glucosidase I and 3.0 mM for β‐glucosidase II. Copyright © 1988 Akademie‐Verlag