title: Leucine biosynthesis in yeast : Identification of two genes (LEU4, LEU5) that affect α-Isopropylmalate synthase activity and evidence that LEU1 and LEU2 gene expression is controlled by α-Isopropylmalate and the product of a regulatory gene.
abstract: Tetrad analysis indicates that α-isopropylmalate synthase activity of yeast is determined by two separate genes, designated LEU4 and LEU5. LEU4 is identified as a structural gene. LEU5 either encodes another α-isopropylmalate synthase activity by itself or provides some function needed for the expression of a second structural gene. The properties of mutants affecting the biosynthesis of leucine and its regulation suggest that the expression of LEU1 and LEU2 (structural genes encoding isopropylmalate isomerase and β-isopropylmalate dehydrogenase, respectively) is controlled by a complex of a-isopropylmalate and a regulatory element (the LEU3 gene product). Similarities and differences between yeast and Neurospora crassa with respect to leucine biosynthesis are discussed.
authors.affiliation: Department of Biochemistry, Purdue University, 47907, West Lafayette, IN, USA.
authors.forename: V R
authors.initials: VR
authors.lastname: Baichwal
authors.forename: T S
authors.initials: TS
authors.lastname: Cunningham
authors.forename: P R
authors.initials: PR
authors.lastname: Gatzek
authors.forename: G B
authors.initials: GB
authors.lastname: Kohlhaw