Fed-batch cultivations of L-isoleucine-producing Escherichia coli TRFP (SGr, α-ABAr, with a pTHR101 plasmid containing a thr operon and ilvA) were carried out on different carbon sources: glucose, sucrose, fructose, maltose and glycerol. The results indicated that sucrose was the best initial carbon source for L-isoleucine production and then sucrose concentration of 30 g·L-1 was determined in ...

The properties of the carrier for isoleucine in Escherichia coli were studied using cytoplasmic membrane vesicles (IM vesicles) prepared by the method of Yamato, Anraku, and Hirosawa (J. Biochem. 77, 705 (1975)). The IM vesicles exhibited respiration-dependent isoleucine transport activity which was more than 30-fold higher than that of "Kaback vesicles" prepared by our hand from the same strai...

Physiological conditions in humans affect plasma amino acid profiles that might have potential for medical use. Because the branched-chain amino acids (BCAAs) leucine, isoleucine and valine are used as medicines and supplements, we investigated the acute effects of individual BCAAs (10-90 mg/kg body weight) or mixed BCAAs ingested as a bolus on plasma amino acid profiles in young healthy men. P...

The synthesis of l-isoleucine with Corynebacterium glutamicum involves 11 reaction steps, in at least five of which activity or expression is regulated. We used four genes and alleles encoding feedback-resistant enzymes (Fbr) in various combinations to assay flux increase through the sequence. During strain construction, the order of genes overexpressed was important. Only when ilvA(Fbr) was fi...

LiCMS (Leptospira interrogans citramalate synthase) catalyses the first reaction of the isoleucine biosynthesis pathway in L. interrogans, the pathogen of leptospirosis. The catalytic reaction is regulated through feedback inhibition by its end product isoleucine. To understand the molecular basis of the high selectivity of the inhibitor and the mechanism of feedback inhibition, we determined t...

1. Threonine deaminase has been purified about 1400fold from extracts of the photosynthetic bacterium Rhodopseudomonas spheroides by ammonium sulfate fractionation and by chromatography on DEAE-cellulose and hydroxylapatite columns. The purified enzyme is almost completely resolved with respect to bound coenzyme, and the activity of holoenzyme is specific for pyridoxal phosphate. The enzyme is ...