The genetics of melezitose fermentation in Saccharomyces

Summary

A multiple series of alleles of the gene MZ exist inSaccharomyces. The members of this series are differentiated from one another by their adaptive response to maltose, turanose, sucrose, melezitose and alpha-methyl glucoside. The more capable members of the series can ferment all five sugars while various multiple alleles are characterized by loss of ability to act on alpha-methyl glucoside, melezitose or sucrose. MZ is linked to the gene MA which controls the production of a specific maltase and to the gene MG which controls the production of a specific alpha-methyl glucosidase. All members of the series of multiple alleles produce the same enzyme showing that the gene and the enzyme are not identical. The enzyme is produced in three different steps, the initial one being a specific reaction of gene with substrate and the final one being a non-specific elicitation of enzyme.