Mutation affecting the specific regulatory control of lysine biosynthetic enzymes in Saccharomyces cerevisiae.

A Saccharomyces cerevisiae mutant which exhibits a considerably increased cellular lysine pool has been isolated and characterized. Assay of enzymes of the lysine and arginine pathways shows that the mutation harboured by this mutant alters the specific repression of lysine but does not influence the general control of amino acid biosynthesis. Because it is recessive to the wild-type allele and acts pleiotropically on the synthesis of several lysine pathway enzymes, this regulatory mutation has been denominated lys80-1 (or lysR--1). It is believed to affect the synthesis or the structure of a factor which plays a negative role in the control of LYS gene expression.