5-Methyltryptophan-resistant mutants derived from Bacillus subtilis strain 168 synthesize all of the tryptophan biosynthetic enzymes constitutively and excrete tryptophan. These mutants can be divided into three classes: class 1, low enzyme level and low rate of tryptophan excretion; class 2, high enzyme level and intermediate rate of tryptophan excretion; and class 3, high enzyme level and hig...

IDO is the rate-limiting enzyme in the kynurenine pathway, catabolizing tryptophan to kynurenine. Tryptophan depletion by IDO-expressing tumors is a common mechanism of immune evasion inducing regulatory T cells and inhibiting effector T cells. Because mammalian cells cannot synthesize tryptophan, it remains unclear how IDO(+) tumor cells overcome the detrimental effects of local tryptophan dep...

Abstract MauG catalyzes the six-electron oxidation of pre-tryptophan tryptophylquinone (preTTQ) cofactor in methylamine dehydrogenase (MADH) to form mature tryptophan (TTQ) via long-range electron transfer. To identify alternative substrates for MauG, docking models 10 tryptophan-like compounds were constructed using Autodock Vina. These demonstrated spontaneous binding preTTQ site with hydroxy...

Newton, W. Austin (University of California, Berkeley), and Esmond E. Snell. Formation and interrelationships of tryptophanase and tryptophan synthetases in Escherichia coli. J. Bacteriol. 89:355-364. 1965.-In addition to the classical tryptophan-repressible tryptophan synthetase (TSase-tr), tryptophan auxotrophs of Escherichia coli contain another distinct tryptophan synthetase (TSase-ti) whic...

Tryptophan was measured in the lumbar CSF and serum of patients undergoing neurological investigation (controls) and in patients with hepatic cirrhosis. Samples were taken from the fasting patients at 8:00 a.m. Under these conditions, in the controls the mean CSF, free )mpm-albumin-bound) and total serum tryptophan were in the approximate ratio 1:4:24. In this cross-sectional study, for the con...

Tryptophan fluorescence lifetimes at pH 2 and pH 8 have been obtained for lysozyme and for lysozyme derivatives in which tryptophan-62 or tryptophan-108 or both are nonfluorescent. The lifetimes range from about 0.5 ns to 2.8 ns for the various emitting tryptophans. The tryptophan lifetimes appear to increase with exposure of tryptophan to solvent, but intramolecular contacts, probably with cys...

dl-Tryptophan (benzene ring-(14)C) and its metabolites persist longer and in greater quantity in tissues of endotoxin-poisoned mice than in tissues of normal mice. Correspondingly less label is excreted in urine and feces and expired as (14)CO(2) in the poisoned animals. The distribution of label (1.1 x 10(6) dpm per microgram of tryptophan) was relatively constant whether it was administered a...

Protein-restriction or deficiency is associated with many pathological disorders. We have made an attempt to study the effect of marginal tryptophan deficiency and supplementation of adequate tryptophan on the activity of antioxidant enzymes in the liver and neuronal tissue of rats. Marginal tryptophan deficiency was created in the animals (group-C) by feeding them with diet consisting of casei...