The β-glucosidase system of Neurospora crassa: III. Further studies on an aryl β-glucosidase mutant

Abstract

The aryl β-glucosidase from a gluc-1 mutant was purified following the procedure adopted for the wild type. In several physical properties like pH optima, thermal inactivation rate at 60 °C and transglycosidase activity, the enzyme from the mutant resembles that of the wild type. Some difference in K_m value toward the substrate PNPG and cellobiose was noted for the two enzymes, and the significance of this point is discussed. Estimation of the specific activities of the two β-glucosidases was done in differential thermal inactivation experiments. Examination of extracts from the isolates of a genetic cross confirmed that the genetic alteration in the gluc-1 mutant specifically concerns the thermostable aryl β-glucosidase.