A VERY STABLE BETA-GLUCOSIDASE FROM A CANDIDA-MOLISCHIANA MUTANT STRAIN - ENZYMATIC-PROPERTIES, SEQUENCING, AND HOMOLOGY WITH OTHER YEAST BETA-GLUCOSIDASES

We purified a beta-glucosidase from the mutant strain Candida molischi ana 35M5N. Analysis of the kinetic properties of this enzyme did not s how any differences between the previously purified wild-type enzyme a nd that of the mutant. Nevertheless, a study of the stability of the e nzyme at different pH levels and temperatures showed the increased res istance of this protein. This enzyme was found to be stable at pH 5 fo r 145 h and retained 78% of its initial activity after the same time a t pH 3.5 (optimal pH) and 30 degrees C. This difference between the wi ld-type and the mutant enzyme could be explained by differences in the quantity or quality of glycosylation. This glycoprotein showed differ ent forms after deglycosylation. Some peptides from this protein were also sequenced. An homology analysis found similarities between this b eta-glucosidase and beta-glucosidases of Candida pelliculosa and Schiz ophyllum commune.