The metabolism of D- and L-[benzene ring-U-14C]tryptophan by dogs was studied. The distribution of label from each isomer in urine, feces, CO2 and various tissues was determined. Thirteen different urinary tryptophan metabolites were isolated by ion exchange cellulose chromatography. D-[14C]Tryptophan was poorly converted to 14CO2 relative to the L-isomer, while giving rise to nearly three time...

The production of L-tryptophan through chemical synthesis, direct fermentation, bioconversion and enzymatic conversion has been reported. However, the role of transport system for aromatic amino acids in L-tryptophan producing strains has not been fully explored. In this study, the fact was revealed that L-tryptophan production and cell growth were affected by the modification of transport syst...

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...

To seek novel antitumor agents, we designed and synthesized new 1-tryptophan analogs based on tryptophan catabolism. 1-Alkyl-tryptophan analogues including 1-ethyltryptophan (1-ET), 1-propyltryptophan (1-PT), 1-isopropyltryptophan (1-isoPT) and 1-butyltryptophan (1-BT) were synthesized from tryptophan. We examined whether those compounds had the antiproliferative effects on SGC7901 and HeLa cel...

L-Tryptophan, an essential amino acid, is readily converted to serotonin, which is thought to be important for expression of slow wave sleep and possibly rapid eye movement (REM) sleep. A vast but often confusing literature exists on L-tryptophan effects on inducing, maintaining, or altering sleep. In this study we measured the effects of L-tryptophan on objective (multiple sleep latency) and s...

In an in vitro study, it was found that aspirin might decrease neopterin production and tryptophan degradation. The aim of the present study was to evaluate the possible association between aspirin use and mean neopterin and tryptophan levels in patients with and without a delirium and whether the use of aspirin is associated with a decreased prevalence of delirium. Neopterin and tryptophan lev...

Tryptophan metabolism plays a key role in several (patho)physiological conditions. In order to study the clinical importance of tryptophan and its predominant metabolites (kynurenines), it is important to be able to measure large series of samples with high accuracy and reliability. We aimed to develop a high-throughput on-line solid-phase extraction-liquid chromatographic-tandem mass spectrome...

The in vivo regulation of intermediate reactions in the pathway of tryptophan synthesis in Neurospora crassa was examined in a double mutant (tr-2, tr-3) which lacks the functions of the first and last enzymes in the pathway from chorismic acid to tryptophan. The double mutant can convert anthranilic acid to indole and indole-3-glycerol, and the production of these indolyl compounds by germinat...

The utilization of the isomers of tryptophan by Lactobacillus arabinosus 17-5 has been studied by several investigators. Greene and Black (1, 2) concluded that n-tryptophan was not utilized by this organism. The procedure outlined for the determination of tryptophan by these investigators was based on the interpretation that nn-tryptophan is exactly onehalf as active as the pure L isomer. Woole...