In a recent paper (1) data were presented to show that acetyl-n-tryptophan was excreted in the feces, whereas acetyl-L-tryptophan was preferentially absorbed and utilized. Three possibilities were presented to explain the absorption of the L isomer: (a) It is deacetylated when passing through the gastrointestinal tract, (b) it is absorbed as acetyl-L-tryptophan and then deacetylated, and (c) bo...

A series of four patients with pulmonary infiltrates, pleural effusions, hypoxemia, peripheral eosinophilia, and symptoms of dyspnea, fatigue, and weakness is reported. Lung tissue obtained in three patients revealed interstitial pneumonitis, small-to-medium-vessel mixed-cell vasculitis, and alveolar exudate of histiocytes and eosinophils. All patients reported ingestion of L-tryptophan-contain...

Mutants of Escherichia coli K-12 that require L-tryptophan (trp) are normally unable to utilize D-tryptophan to fulfill their requirement. However, secondary mutations (dadR) that confer this ability can be isolated. In such strains two distinct enzymes are found to be produced at high levels: D-amino acid oxidase (EC 1.4.3.3) and D-tryptophan oxidase. A convenient assay procedure for D-tryptop...

The activation of the apoenzyme of tryptophan pyrrolase in preparations from hydrocortisone-induced rats was shown to consist of two separate, sequential steps, only the second of which is necessary to activate preparations from tryptophan-induced rats. These reactions are as follows. (a) Conjugation of the apoenzyme to the oxidized holoenzyme with hematin supplied by added methemoglobin, a rea...

In order to ascertain whether autistic children display characteristic metabolic signatures that are of diagnostic value, plasma amino acid analyses were carried out on a cohort of 138 autistic children and 138 normal controls using reverse-phase HPLC. Pre-column derivatization of amino acids with phenyl isothiocyanate forms phenyl thio-carbamate derivates that have a lamba(max) of 254 nm, enab...

Tumor immune escape mechanisms are being regarded as suitable targets for tumor therapy. Among these, tryptophan catabolism plays a central role in creating an immunosuppressive environment, leading to tolerance to potentially immunogenic tumor antigens. Tryptophan catabolism is initiated by either indoleamine 2,3-dioxygenase (IDO-1/-2) or tryptophan 2,3-dioxygenase 2 (TDO2), resulting in biost...

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20) catalysed hydrogen-deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine at pH 7.8. 1H-NMR has also been used to follow the tryptophan-synthase-catalysed hydrogen-deuterium exchange of the alpha-protons of a range of L- and D-amino acids at pH 7.8. The pK(a) values of the alpha-protons of these amino acids hav...

Complex regional pain syndrome (CRPS) is a severe chronic pain condition that most often develops following trauma. Blood samples were collected from 220 individuals, 160 CRPS subjects, and 60 healthy pain-free controls. Plasma amino acid levels were compared and contrasted between groups. L-Aspartate, L-glutamate, and L-ornithine were significantly increased, whereas L-tryptophan and L-arginin...

Pseudomonas acidovorans has been studied by laser pulse, flash photolysis. Previous studies demonstrated that saturation of the catalytic and allosteric sites of the enzyme by L-tryptophan resulted in a 28-fold increase in the equilibrium constant for carboxyenzyme complex formation (MAENO, H., AND FEIGELSON, P. (1968) J. Biol. Chem. 243, 301-305). The present studies have shown that the predom...

BACKGROUND As bacteria-originated crude violacein, a natural indolocarbazole product, consists of violacein and deoxyviolacein, and can potentially be a new type of natural antibiotics, the reconstruction of an effective metabolic pathway for crude violacein (violacein and deoxyviolacein mixture) synthesis directly from glucose in Escherichia coli was of importance for developing industrial pro...