Herman, Alberta (University of Wisconsin, Madison) and Harlyn Halvorson. Identification of the structural gene for beta-glucosidase in Saccharomyces lactis. J. Bacteriol. 85:895-900. 1963.-Three allelic forms (B(h, m, l)) of the structural gene for beta-glucosidase have been identified in the yeast Saccharomyces lactis. Evidence that these are structural gene alleles includes the independent expression of the alleles in homozygous and heterozygous diploids and differences in the specificity and in the physical properties of the enzyme produced in response to the various allelic mutations. Two factors, one controlling production of the pulcherrimin-like pigment, the other beta-galactosidase activity, are linked to the B locus. The beta-glucosidase in these strains hydrolyzes the chromogenic substrate, p-nitrophenyl-beta-d-glucoside, arbutin, salicin, and esculin. Cellobiose, on the other hand, is hydrolyzed by another enzyme.