Human fibroblast interferon binds to L-tryptophan, D-tryptophan, L-phenylalanine, and L-tyrosine, all immobilized directly to cyanogen bromide-activated agarose, as well as to L-tryptophan and D-tryptophan methyl ester, both immobilized via molecular arms. The retention of fibroblast interferon is selective and results in a 2300-fold purification. Human leukocyte interferon binds neither to L-t...

A transaminase (aminotransferase, EC 2.6.1) fraction was partially purified from shoot tips of pea (Pisum sativum L. cv. Alaska) seedlings. With alpha-ketoglutarate as co-substrate, the enzyme transaminated the following aromatic amino acids: d,l-tryptophan, d,l-tyrosine, and d,l-phenylalanine, as well as the following aliphatic amino acids: d,l-alanine, d,l-methionine, and d,l-leucine. Of othe...

BACKGROUND L-tryptophan is an aromatic amino acid widely used in the food, chemical and pharmaceutical industries. In Escherichia coli, L-tryptophan is synthesized from phosphoenolpyruvate and erythrose 4-phosphate by enzymes in the shikimate pathway and L-tryptophan branch pathway, while L-serine and phosphoribosylpyrophosphate are also involved in L-tryptophan synthesis. In order to construct...

Nonalcoholic fatty liver disease is one of the most common liver diseases. L-tryptophan and its metabolite serotonin are involved in hepatic lipid metabolism and inflammation. However, it is unclear whether L-tryptophan promotes hepatic steatosis. To explore this issue, we examined the role of L-tryptophan in mouse hepatic steatosis by using a high fat and high fructose diet (HFHFD) model. L-tr...

Tryptophan 2,3-dioxygenase [L-tryptophan--oxygen 2,3-oxidoreductase (decyclizing), EC 1.13.11.11] has been reported to act solely on the L-isomer of tryptophan. However, by using a sensitive assay method with D- and L-[ring-2-14C]tryptophan and improved assay conditions, we were able to demonstrate that both the D- and L-stereoisomers of tryptophan were cleaved by the supernatant fraction (3000...

Multi-walled carbon nanotubes (MWCNTs) were immobilized on the surface of a glassy carbon electrode (GCE) in the presence of cetyltrimethylammonium bromide (CTAB) to form a MWCNTs-CTAB nanocomposite-modified electrode. The electrocatalytic response of the modified electrode towards tryptophan (Trp) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The surface...

The aim of the present work was to determine whether the administration of melatonin or L­-tryptophan (a precursor of melatonin) affects the immune responses and performance of broilers during induced exposure to aflatoxins in feed. The study was conducted from 0-6 weeks comprising six dietary treatments in triplicate with10 chickens in each replicate. The diets were formulated to supply 23% cr...

The metabolism of n-tryptophan in man was recently studied by Langner and Berg (l), who found that about one-third to one-half of a 2 gm. dose was excreted unchanged in the urine. Considerable n-kynurenine and traces of indolepyruvic acid and acetyltryptophan were also excreted by their subjecm. Langner and Volkmann (2) found that acetyl-n-tryptophan was poorly absorbed and most of the compound...

Binding of bilirubin and of L-tryptophan to dansylated albumins was investigated. Dansylation of less than one lysine residue per molecule of albumin did not affect the bilirubin binding, but decreased the L-tryptophan binding, indicating that dansylation had taken place in or near the l-tryptophan-binding site. Native albumin and albumin-bilirubin 1:1 complex showed the same affinity for L-try...