DNA sequence of the tryptophan synthase genes of Pseudomonas putida.
Tryptophan synthase: the workings of a channeling nanomachine.
The reaction of indole with the aminoacrylate intermediate of Salmonella typhimurium tryptophan synthase: observation of a primary kinetic isotope effect with 3-[(2)H]indole.
A convenient enzymatic synthesis of L-halotryptophans.
Serotonin is an important neurotransmitter that the brain produces from tryptophan contained in foods such as “clams, oysters, escargots, octopus, squids, banana, pineapple, plum, nuts, milk, turkey”, spinach, and eggs (1). Functions of serotonin include the regulation of sleep, appetite, and impulse control. Increased serotonin levels are related to mood elevation. Wurtman and Wurtman (1989) developed a theory suggesting that a diet rich in carbohydrates can relieve depression and elevate mood in disorders such as carbohydrate craving obesity, pre-menstrual syndrome, and seasonal affective disorder (SAD) (5). They theorized that increased patients’ carbohydrate intake associated with these disorders represented self-medicating attempts and that carbohydrates increased serotonin synthesis. A protein rich diet, in contrary, decreases brain serotonin levels.
tryptophan (targets tryptophan synthesis ..
Time-resolved fluorescence anisotropy study of the refolding reaction of the alpha-subunit of tryptophan synthase reveals nonmonotonic behavior of the rotational correlation time.
Regulation of enzyme synthesis in the tryptophan pathway of ..
BetaQ114N and betaT110V mutations reveal a critically important role of the substrate alpha-carboxylate site in the reaction specificity of tryptophan synthase.
16/06/2015 · Tryptophan vs
Evidence that mutations in a loop region of the alpha-subunit inhibit the transition from an open to a closed conformation in the tryptophan synthase bienzyme complex.
Melatonin: Which Helps with Sleep More
Enzyme derepression and feedback inhibition of the first enzyme are the regulatory mechanisms demonstrated for the tryptophan pathway in Saccharomyces cerevisiae. The relative contributions of the two mechanisms to the control of the flux through the pathway in vivo were analyzed by (i) measuring feedback inhibition of anthranilate synthase in vivo, (ii) determining the effect of regulatory mutations on the level of the tryptophan pool and the flux through the pathway, and (iii) varying the gene dose of individual enzymes of the pathway at the tetraploid level. We conclude that the flux through the pathway is adjusted to the rate of protein synthesis by means of feedback inhibition of the first enzyme by the end product, tryptophan. The synthesis of the tryptophan enzymes could not be repressed below a basal level by tryptophan supplementation of the media. The enzymes are present in excess. Increasing or lowering the concentration of individual enzymes had no noticeable influencing on the overall flux to tryptophan. The uninhibited capacity of the pathway could be observed both upon relieving feedback inhibition by tryptophan limitation and in feedback-insensitive mutants. It exceeded the rate of consumption of the amino acid on minimal medium by a factor of three. Tryptophan limitation caused derepression of four of the five tryptophan enzymes and, as a consequence, led to a further increase in the capacity of the pathway. However, because of the large reserve capacity of the "repressed" pathway, tryptophan limitation could not be imposed on wild-type cells without resorting to the use of analogs. Our results, therefore, suggest that derepression does not serve as an instrument for the specific regulation of the flux through the tryptophan pathway.