Properties of the -Glucosidases of Talaromyces emersonii

The thermophilic fungus Talaromyces emersonii when grown on cellulose-containing medium produces three extracellular forms of β-glucosidase, I(M r 135000), II (M r, 100000), III (M r, 45700), and one intracellular form, β-glucosidase IV (M r, 57600). With the exception of β-glucosidase II which has yet to be isolated in quantities sufficient for characterization each has been shown to be a glycoprotein and to exist as a single polypeptide. Each of the purified enzyme preparations catalysed cellobiose hydrolysis but only β-glucosidase IV, at the concentrations of substrates used, also catalysed glucosyl transfer to cellobiose.