The essential amino acid L-tryptophan (Trp) has importance as a pharmaceutical agent, especially in neuro-medicine. It is also added to feed products as a food fortifier. Furthermore, application of Trp is widespread in biotechnology. Trp is produced by a condensation reaction between indole and Lserine, which is catalyzed by bacterial tryptophanase activity. In this study, we have investigated...

Tryptophanase, encoded by the gene tnaA, is a catabolic enzyme distinct from the enzymes of tryptophan biosynthesis. Tryptophanase synthesis is induced by tryptophan and is subject to catabolite repression. We studied the mechanism of tna operon induction. Mutants with altered rho factor were partially constitutive for tna expression, implicating rho-dependent transcription termination in the c...

When Escherichia coli K-12 is grown anaerobically in medium containing tryptophan and sodium nitrate, it produces red compounds. The reaction requires functional genes for trytophanase (tnaA), a tryptophan permease (tnaB), and a nitrate reductase (narG), as well as a natural drop in the pH of the culture. Mass spectrometry revealed that the purified chromophores had mass/charge ratios that clos...

FILDES [1938], referring to the claims of Happold & Hoyle [1936] that 'the failure to produce indole by cultures of E. coli grown in the presence of glucose is due to the non-production of a tryptophanase system', suggests that this is but a partial truth and that the tryptophanase system in the cells consists oftwo parts, a ' constitutive' part and an 'adaptive' part, ofwhich only the 'adaptiv...

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eli...

Shikunshito-Kamiho (SKTK) is a traditional Chinese medicine composed of eight crude drugs (Ginseng Radix, Hoelen, Atractylodis Rhizoma, Glycyrrhizae Radix, Prunellae Spica, Ostreae Testa, Laminaria Thallus, Sargassum). We investigated the effects of SKTK on pH, ammonia, fecal enzymes such as beta-glucuronidase, tryptophanase, urease, and formation aberrant crypt foci in the colon carcinogenesis...

A culture of stationary phase Escherichia coli cells has been reported to produce copious indole when exposed to high temperature (50°C), and this response has been proposed to aid survival. We reinvestigated this phenomenon and found that indole production under these conditions is probably not a direct response to heat stress. Rather, E. coli produces indole when growth is prevented, irrespec...