Mode of Conversion of Asparto, β-Semialdehyde tol-Threonine andl-Lysine inBrevibacterium lactofermentum

Improvedl-Threonine Production by the Amplification of the Gene Encoding Homoserine Dehydrogenase inBrevibacterium lactofermentum

“…After single colony isolation, the drug resistancy of each colony· was investigated. Potent L-threonine producing mutants of B. flavum 7 ,9) and also B. lactofermentum 10 ) had been reported. In these mutants, HD had been shown to become genetically insensitive to the feedback inhibition by L-threonine.…”

“…In these mutants, HD had been shown to become genetically insensitive to the feedback inhibition by L-threonine. 8 ,10) B. lactofermentum mutant M _IS 10 ) accumulated Lthreonine and L-Iysine simultaneously owing to the genetic desensitization of aspartokinase to the feedback inhibition by L-threonine plus L-Iysine in addition to the desensitization of HD (Fig. 1).…”

Sequence Analysis of Functional Regions of Homoserine Dehydrogenase Genes froml-Lysine andl-Threonine-producing Mutants ofBrevibacterium lactofermentum

“…In this strain, the feedback inhibition of HD by threonine was desensitized. 4 ) As for the region regarding feedback inhibition of this enzyme, previous studies offeedback-insensitive mutants from C. glutamicum have shown that the C-terminal sequence forms the regulatory domain involved in the threonine recognition or binding site for feedback inhibition.…”