Mutants of Streptomyces akiyoshiensis blocked in 5-hydroxy-4-oxonorvaline production.

hydrogenase, thus blocking the biosynthesis of threonine, isoleucine and methionine2). Because these are essential dietary amino acids in animals, HONis potentially useful as a nontoxic antimicrobial drug. In addition, it may have value as a chiral starting material for the synthesis of more complex pharmaceutical agents. Analyses of HONenriched from isotopically labelled precursors have shown that C-l to C-4 are derived from aspartate, and C-5 from the methyl carbon of acetate40, but the