Involved in the biosynthesis of the branched chain amino acids leucine, isoleucine, and valine. Catalyzes the formation of methionine from 2-keto-4-methylthiobutyrate (KMTB) in the methionine salvage pathway primarily using branched chain amino acids (leucine, isoleucine, and valine) as the amino donors. Appears to be involved in the regulation of the transition from G1 to S phase in the cell cycle. High copy suppressor of a temperature-sensitive mutation in the ABC transporter, ATM1. 2-oxoglutarate + L-leucine = 4-methyl-2-oxopentanoate + L-glutamate 2-oxoglutarate + L-isoleucine = (S)-3-methyl-2-oxopentanoate + L-glutamate 2-oxoglutarate + L-valine = 3-methyl-2-oxobutanoate + L-glutamate Amino-acid biosynthesis; L-isoleucine biosynthesis; L-isoleucine from 2-oxobutanoate: step 4/4. Amino-acid biosynthesis; L-leucine biosynthesis; L-leucine from 3-methyl-2-oxobutanoate: step 4/4. Amino-acid biosynthesis; L-valine biosynthesis; L-valine from pyruvate: step 4/4. Amino-acid biosynthesis; L-methionine biosynthesis via salvage pathway; L-methionine from S-methyl-5-thio-alpha-D-ribose 1-phosphate: step 6/6. Highly expressed during logarithmic phase of growth. Down-regulated during the stationary phase. Mainly expressed on ammonium-glucose exponential cultures (biosynthetic conditions), and repressed in the presence of leucine, isoleucine or valine. Present with 87300 molecules/cell in log phase SD medium. Belongs to the class-IV pyridoxal-phosphate-dependent aminotransferase family.