Repression of the formation of biosynthetic enzymes by the ultimate end product of their action has been shown to be an important aspect of metabolic regulation in microorganisms.1 In Escherichia coli and Salmonella typhimuwium each of the last four steps in the synthesis of valine and isoleucine is catalyzed by the same enzymes.2 Repression of these enzymes presents a unique situation since tw...

The amino acids L-arginine, L-isoleucine, L-leucine, L-methionine, L-serine, L-threonine, and L-valine were essential for the growth of Legionella pneumophila in a chemically defined medium. A partial requirement for L-cysteine (or L-cystine) was also observed. A minimal medium containing only the eight required amino acids supported the growth of this bacterium only if the medium was supplemen...

1. Three peptides containing alpha-aminoadipic acid and cysteine have been obtained in small amounts from the mycelium of a Cephalosporium sp. 2. The peptides were precipitated as cuprous mercaptides together with glutathione and resolved from the latter and from each other by preparative paper electrophoresis and chromatography either in the sulphonic acid form or as S-sulphonyl derivatives. F...

Various new chiral ligands have been synthesized by the condensation of different esters of L-Valine with different substituted salicylaldehydes in order to find the most effective catalyst for the enantioselctive ketone reduction. Chiral amine synthesized from L-Valine methyl ester and 5-chloro salicylaldehyde is found to catalyse the enantioselective reduction of prochiral ketone with high yi...

Isotope labeling of recombinant proteins is a prerequisite for application of nuclear magnetic resonance spectroscopy (NMR) for the characterization of the three-dimensional structures and dynamics of proteins. Overexpression of isotopically labeled proteins in bacterial or yeast host organisms has several drawbacks. In this work, we tested whether the recently described eukaryotic protein expr...

Twenty putative aminotransferase (AT) proteins of Corynebacterium glutamicum, or rather pyridoxal-5'-phosphate (PLP)-dependent enzymes, were isolated and assayed among others with L-glutamate, L-aspartate, and L-alanine as amino donors and a number of 2-oxo-acids as amino acceptors. One outstanding AT identified is AlaT, which has a broad amino donor specificity utilizing (in the order of prefe...

The title compound, C(19)H(30)ClNO(5), was obtained by the tandem asymmetric Michael addition-elimination reaction of (5S)-3,4-dichloro-5-(l-menth-yloxy)furan-2(5H)-one and l-valine in the presence of potassium hydroxide. The furan-one unit is approximately planar (r.m.s. deviation = 0.0204 Å) and the six-membered cyclo-hexane ring adopts a chair conformation. The crystal structure is stabilize...

1. The conductivities of aqueous solutions of glycine, d,l-valine, and l-asparagine have been determined, and comparisons have been made with similar data reported in the literature. 2. On the basis of certain theoretical considerations, calculations of the expected conductivities of aqueous solutions of glycine, asparagine, aspartic acid, and glutamic acid have been made and these data have be...