Anthranilate synthetase was purified by ammonium sulfate precipitation and gel filtration from extracts of an episomebearing Escherichia coli mutant grown under conditions of tryptophan pathway derepression. This purification represented an l&fold increase in specific activity over the activity of the derepressedmutant extract. Starch gel electrophoresis and ultracentrifugation revealed only sl...

Podophyllum hexandrum is an endangered, commercial source of a naturally occurring lignan podophyllotoxin, which is a precursor of potent anticancer drugs. Cell suspension cultures were established using four-year-old cell line RC4 of P. hexandrum in liquid P1 medium [half strength B5 basal medium supplemented with 1% (w/v) sucrose, 2,4-D (1 mg/l), GA3 (1 mg/l) and BA (0.1 mg/l)]. The effect of...

A Bombyx mori L. (Lepidoptera: Bombycidae) gene encoding tryptophan oxygenase has been molecularly cloned and analyzed. The tryptophan oxygenase cDNA had 1374 nucleotides that encoded a 401 amino acid protein with an estimated molecular mass of 46.47 kDa and a PI of 5.88. RT-PCR analysis showed that the B. mori tryptophan oxygenase gene was transcribed in all examined stages. Tryptophan oxygena...

BACKGROUND Serotonin (5-HT) is released from enterochromaffin cells in the gastrointestinal tract. 5-HT, via the activation of 5-HT2 and 5-HT3 receptors on vagal fibers, mediates pancreatic secretion through the mechanism independent from cholecystokinin. Melatonin (5-HT derivative) or L-tryptophan (melatonin or 5-HT precursor) given systemically or intraduodenally to the rats stimulate amylase...

There is much interest in understanding the pathways that trigger biosynthesis of the plant hormone auxin. In this issue, Stepanova et al. (2008) and Tao et al. (2008) reveal that a small family of tryptophan aminotransferases catalyze formation of indole-3-pyruvic acid (IPA) from L-tryptophan (L-Trp), the first step in a pathway for auxin biosynthesis.

A symbiotic strain was isolated from the root nodules of the legume pulse Phaseolus mungo L and designated as PM 25. The strain was identified as Rhizobium sp. on the basis of the physiobiochemical characteristics and 16S rDNA sequence based homology. The Minimum Inhibitory Concentration of the analogue 5-fluro-tryptophan was 3.0 mM. The analogue (5FT) resistant mutants were screened from wild ...

AIMS 3-Methylindole (3-MI) is a degradation product of L-tryptophan and is both an animal waste malodorant and threat to ruminant health. Culture conditions influencing 3-MI production in Clostridium scatologenes ATCC 25775 were investigated. METHODS AND RESULTS Extracellular 3-MI levels in cells cultured in brain heart infusion (BHI) medium (pH 7.0) at 33 degrees C and 37 degrees C for 72 h ...

Melatonin, a pineal hormone, is also produced in the gastrointestinal tract. Melatonin receptors have been detected in the stomach, intestine and pancreas. This indole inhibits insulin secretion but its role in the physiological modulation of exocrine pancreatic function is yet unknown. The aim of this study was to evaluate the pancreatic secretory effect of melatonin and its precursor; L-trypt...

A crystal structure redetermination of the L-tryptophan picrate crystal previously studied by Ishida et al. (Chem. Pharm. Bull. 41 (1993) 433-438) showed that it comprises L-tryptophan L-tryptophanium dimeric cation, one picrate anion and picric acid. The O⋯O distance of the O-H⋯O hydrogen bond in the dimeric cation is equal to 2.470(6) Å. The infrared spectrum of the crystal was registered and...

Free tryptophan in plasma was separated by centrifugation through an Amicon ultrafiltration membrane cone. The value obtained without control of pH was found to be lower than that obtained with control of pH by an improved method ( Hijikata et al. (1981) Anal. Biochem. 118, 10-16). For determination of the total tryptophan concentration in the plasma, high performance liquid chromatography (HPL...