in the present paper, the use of a novel carbon paste electrode modified by 7,8-dihydroxy-3,3,6-trimethyl-3,4-dihydrodibenzo[b,d]furan-1(2h)-one (dtd) and oxidized multi-walled carbon nanotubes (ocnts) is described for determination of levodopa (ld), acetaminophen (ac) and tryptophan (trp) by a simple and rapid method. at first, the electrochemical behavior of dtd is studied, then, the mediated...

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...

Tryptophan was isolated from rat feces as an active compound against ovalbumin permeation in an in vitro Caco-2 cell model. Tryptophan dose-dependently inhibited ovalbumin permeation with accompanying increase in transepithelial electric resistance, and its inhibitory activity reached a plateau at 10 mM. Brown Norway rats were sensitized by intragastric administration of ovalbumin together with...

1512 CLINICALCHEMISTRY,Vol. 26, No. 10, 1980 lution containing 1.25 smolfL was degraded after 1 mm. When exposed to light of wavelength 254 nm, tryptophan was alsorapidlydegraded,although less quickly than in bright sunlight: 64% in the 5 itmol/L solution was destroyed after 15 mm exposure,whileatthelower concentration no detectable tryptophan remained after 30-mm exposure. Tryptophan in the su...

Tryptophan catabolism in cancer is increasingly being recognized as an important microenvironmental factor that suppresses antitumor immune responses. It has been proposed that the essential amino acid tryptophan is catabolized in the tumor tissue by the rate-limiting enzyme indoleamine-2,3-dioxygenase (IDO) expressed in tumor cells or antigen-presenting cells. This metabolic pathway creates an...

Abstract Gut microbial dysbiosis has been associated with the development of systemic lupus erythematosus (SLE). Dietary tryptophan modifies composition gut microbiota as well disease activity in a lupus-prone mouse (TC). To directly test modulatory function on microbiota, we transplanted from TC and B6 control mice into germ-free or antibiotic treated recipients fed high low dietary tryptophan...

Phosphorescence spectroscopy has been used to probe the microenvironments of the tryptophan residues of the cyclic antibiotic decapeptides tyrocidine B (which contains a single tryptophan residue) and tyrocidine C (which contains 2 tryptophan residues). Both peptides exhibited two distinct, overlapping tryptophan phosphorescence emission spectra under appropriate solvent conditions. The two emi...

Previous studies with mutants of Neurospora crassa lacking the enzyme tryptophan synthetase (indole + L-serine -> L-tryptophan) have shown that certain of these strains form large amounts of a protein which is immunologically cross reacting and hence probably structurally related to the enzyme (Suskind et al., 1955). One mutant strain which, by genetic criteria, was allelic with' the other muta...