A pot experiment was conducted in the screen of the National Research Centre during two successive seasons to study the response of periwinkle plants to foliar spray with tryptophan or putrescine at the concentrations 10 M, 10 M or 10 M. The obtained data indicated that exogenous application of tryptophan or putrescine on periwinkle transplants considerably increased plant growth at successive ...

Tissue inhibitor of metalloproteinases (TIMPs) are endogenous inhibitor proteins of matrix metalloproteinases and contain 12 cysteine residues that are conserved among TIMPs, and which are important for their activity and structure. In the present study, three tryptophan residues conserved among TIMPs were revealed to be important for the secretion of TIMP-2. Replacement of conserved tryptophan...

The regulation of serotonin synthesis in the central nervous system seems to involve mechanisms which control the intracellular concentration of tryptophan and the hydroxylation step . Numerous situations are reviewed which demonstrate that changes in the concentration of free tryptophan in plasma and/or in the uptake of the amino acid in brain may alter tryptophan concentration and 5-HT synthe...

BACKGROUND Patients with cancer often suffer from fatigue and decreased quality of life which might be related to the breakdown of essential amino acid tryptophan. METHODS In 50 patients with lung cancer we examined fatigue and the deterioration of quality of life in patients using the Functional Assessment of Cancer Therapy Anemia (FACT-An) and -Fatigue (FACT-F) subscales of FACT-General and...

1. Tryptophan inhibition of gluconeogenesis in isolated rat liver cells is characterized by a 20 min lag period before linear rates of glucose output are attained. 2. Half-maximal inhibition of gluconeogenesis in isolated rat hepatocytes is produced by approx. 0.1 mM-tryptophan. 3. Tryptophan inhibits gluconeogenesis from all substrates giving rise to oxaloacetate, but stimulates glycerol-fuell...

Parenteral administration of tryptophan has been shown to increase markedly rat liver tryptophan pyrrolase activity (1). This phenomenon is often referred to as induction or adaptation due to its similarity to substrate-induced enzyme formation in microorganisms. The preceding article (2) documents the presence of a factor in microsomes which activates tryptophan pyrrolase of normal liver cell ...

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...

Gamma interferon (IFN-gamma) affects tryptophan metabolism by mediating the expression of indoleamine 2,3-dioxygenase and tryptophanyl-tRNA synthetase. In the present study, we investigated the role of indoleamine 2,3-dioxygenase-mediated tryptophan depletion in the induction of tryptophanyl-tRNA synthetase by IFN-gamma. The addition of excess tryptophan to the culture medium did not affect the...

A regulatory relationship in Bacillus subtilis between histidine and the synthesis of tryptophan exemplifies “metabolic interlock,” a phenomenon of regulatory interactions exerted between biochemical pathways. The enzymatic basis for the histidine-tryptophan relationship was examined. Histidine activates anthranilate synthetase by increasing the apparent value of VmSx. Hence, histidine antagoni...