The kynurenine pathway is the major route of L-tryptophan (L-Trp) catabolism in biology, leading ultimately to the formation of NAD(+). The initial and rate-limiting step of the kynurenine pathway involves oxidation of L-Trp to N-formylkynurenine. This is an O2-dependent process and catalyzed by indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase. More than 60 years after these dioxygena...

Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solution (pH 6.0) using a carbon nanotube paste electrode (CNPE) modified with p-aminophenol as a mediator. The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of L-cysteine, leading to an overpotential reduced by more than 550 mV. Using diffe...

The radioprotective ability of L-tryptophan, tryptamine, 3-indoleacetic and indole (10~4 m), on UV and gamma irradiated DNA (10-4 m) is studied. UV radioprotection is accomplished in the following order of efficiency: L-Tryptophan and 3-indoleacetic acid > indole and tryptamine. The corresponding DRF measured as absorbancy loss at 260 nm, were: L-Tryptophan and 3-indoleacetic acid around 3 and ...

Quinoxaline-2-carboxylic acid (QXC) and 3-hydroxyquinaldic acid (HQA) feature in quinomycin family and confer anticancer activity. In light of the significant potency against cancer, the biosynthetic gene clusters have been reported from many different Streptomyces strains, and the biosynthetic pathway were proposed mainly based on the in vivo feeding experiment with isotope labeled putative in...

We reported previously that the pellagragenic property of corn protein is not only low l-tryptophan concentration but also the lower conversion percentage of l-tryptophan to nicotinamide; the amino acid composition greatly affected the conversion percentage. The amino acid value of wheat protein is lower than that of rice protein. In the present study, we compare the conversion percentages of l...

There are indications that serotonergic neurotransmission is disturbed in several psychiatric disorders. One explanation may be disturbed transport of tryptophan (precursor for serotonin synthesis) across cell membranes. Human fibroblast cells offer an advantageous model to study the transport of amino acids across cell membranes, since they are easy to propagate and the environmental factors c...