Induction and genetics of two alpha-galactosidase activities in Saccharomyces cerevisiae

Summary The induction of -galactosidase of Saccharomyces cerevisiae was investigated. We have demonstrated the existence of inducible internal and external -galactosidase activities and have studied the relationship between the two -galactosidases by examining a mutant strain which lacks both the internal and external activities. The mutant possesses a mutation in a single locus (mel 1-1) which does not affect the synthesis of the other galactose pathway enzymes or the ability of the yeast to grow on media containing only galactose as the carbon source. Genetic studies of the mutant indicate that mel 1-1 is recessive and allelic to the wild type allele for melibiose fermentation Mel 1.This investigation was supported in part by Grant No. AM15325 from the National Institutes of Arthritis, Metabolism and Digestive Diseases, and a grant from the Office of Research Administration, University of Hawaii. R.G. Buckholz was a National Science Foundation Pre-Doctoral Fellow during part of this study