Indoleamine 2, 3-dioxygenase (IDO) is the first and rate limiting catabolic enzyme in the degradation pathway of the essential amino acid tryptophan. By cleaving the aromatic indole ring of tryptophan, IDO initiates the production of a variety of tryptophan degradation products called "kynurenines" that are known to exert important immuno-regulatory functions. Because tryptophan must be supplie...

We report a rapid, simple, and sensitive spectrofluorometric procedure for total serum or plasma tryptophan. Plasma deproteinization, tryptophan extraction, and pH optimization are all carried out with a buffered cellulose/ethanol reagent. The fluorescence is measured at an emission wavelength of 350 nm, on excitation of 290 nm. Tryptophan fluorescence relative to concentration is linear up to ...

The major antimalarial drug quinine perturbs uptake of the essential amino acid tryptophan, and patients with low plasma tryptophan are predisposed to adverse quinine reactions; symptoms of which are similar to indications of tryptophan depletion. As tryptophan is a precursor of the neurotransmitter serotonin (5-HT), here we test the hypothesis that quinine disrupts serotonin function. Quinine ...

Tryptophanase, an enzyme with extreme absolute stereospecificity for optically active stereoisomers, catalyzes the synthesis of l-tryptophan from l-serine and indole through a beta-substitution mechanism of the ping-pong type, and has no activity on d-serine. We previously reported that tryptophanase changed its stereospecificity to degrade d-tryptophan in highly concentrated diammonium hydroge...

First principles density functional theory calculations are performed on tryptophan-ZnO nanoparticles complex in order to study site specific interactions between tryptophan and ZnO. The calculated results find the salt bridge structure involving the -COOH group and ZnO cluster to be energetically more favorable than other interacting sites, such as indole and amine groups in tryptophan. The in...

Mammals, including humans, can synthesize the vitamin nicotinamide from tryptophan in the liver. The resultant nicotinamide is distributed to non-hepatic tissues. We have studied the effects of changes in tryptophan-nicotinamide metabolism on niacin nutritional status. The liver plays a critical role in nicotinamide supply. Animal studies showed that the tryptophan-nicotinamide pathway is affec...

Patients with uraemic encephalopathy were previously found to have low total tryptophan (bound plus free), but high free tryptophan concentrations in the plasma and high CSF tryptophan concentrations. The 5-hydroxytryptamine metabolite 5-hydroxyindoleacetic acid was also raised in the CSF. A study of the effect of dialysis treatment on these substances in chronic uraemic patients with and witho...

ABSTRACT: Depression is a frequent mental disorder that can cause great suffering and affect performance in daily activities. Tryptophan, an essential amino acid precursor to serotonin, has been associated with the development of depression. The objective was analyze relationship between components from diet appearance depressive symptoms. An integrative literature review carried out SciElo, LI...

Organ cultures of individual rat pineals incorporate (14)C-tryptophan into proteins at a nearly constant rate for at least 48 hours. Previous studies have shown that these cultures also convert (14)C-tryptophan to serotonin, melatonin, and 5-hydroxyindoleacetic acid, and release these indoles into the media. The formation of (14)C-protein from (14)C-tryptophan is accelerated by the addition to ...

Chemical modifications of rye seed chitinase-c (RSC-c) with yarious reagents suggested the inyolyements of tryptophan and glutamiclaspartic acid residues in the activity. Of these, the modification of tryptophan residues wjth ?V・bromosuccinimide (NBS) was inyestigated in detail. In the NBS-oxidation at pH 4.0, two of the six tryptophan residues in RSC-c were rapidly oxidized and the chitinase a...