Regulation of the biosynthesis of four of the five enzymes of the isoleucine-valine pathway was studied in Saccharomyces cerevisiae. A method is described for limiting the growth of a leucine auxotroph by using valine as a competitor for the permease. Limitation for isoleucine and valine was accomplished by the use of peptides containing these amino acids conjugated with glycine as nutritional ...

Nonprotein amino acid furanomycin was found to bind with Escherichia coli isoleucyl-tRNA synthetase (IleRS) almost as tightly as the substrate L-isoleucine. The conformation of furanomycin bound to the enzyme was determined by NMR analyses including the transferred nuclear Overhauser effect method. The conformation of IleRS-bound furanomycin was similar to that of L-isoleucine, although the che...

Antimicrobial peptides represent an important component of the innate immune defenses of living organisms, including humans. They are broad-spectrum surface-acting agents secreted by the epithelial cells of the body in response to infection. Recently, L-isoleucine and its analogues have been found to induce antimicrobial peptides. The objectives of the study were to examine if addition of L-iso...

A threonine deaminase susceptible to inhibition by isoleucine was purified over 3,000-fold from extracts of Pseudomonas multivorans, a bacterium able to use threonine or alpha-ketobutyrate as sole source of carbon and energy. The enzyme was characterized with respect to molecular weight, dissociation to subunits, and apparent affinities for threonine, isoleucine, and several other ligands. Cert...

The enzyme dipeptidase-A (DIP-A) in Drosophila melanogaster is coded by a second chromosome locus that is polymorphic for three allozymes in natural populations. DIP-A appears to be the only enzyme in D. melanogaster capable of hydrolyzing the dipeptide glycyl-L-isoleucine, since flies homozygous for null alleles at this locus have no detectable glycyl-L-isoleucine-ase activity. DIP-A activity ...

Branched-chain amino acids increase the brain perfusion of patients with hepatic encephalopathy (HE), but the amino acid and the mechanisms involved are still unknown. This study compared brain perfusion and clinical improvement during leucine or isoleucine supplementation. After randomization, 27 subjects with cirrhosis and HE received leucine or isoleucine supplements for one year. Brain sing...

The hydrophobic dl-amino acids alanine, valine, leucine, and isoleucine have been cocrystallized with LiCl via solid-state solution methods, the effect of preparation conditions solvent choice on racemic versus conglomerate formation has investigated. For sake comparison, enantiopure l-amino also reacted in same experimental conditions. With dl-alanine only, a ionic cocrystal formula dl-alanine...

Coexpression of di-alpha-globin and beta-globin in Escherichia coli in the presence of exogenous heme yielded high levels of soluble, functional recombinant human hemoglobin (rHb1.1). High-level expression of rHb1.1 provides a good model for measuring mistranslation in heterologous proteins. rHb1.1 does not contain isoleucine; therefore, any isoleucine present could be attributed to mistranslat...