Tryptophan products

Enzymatic Process. Chemically synthesized substrates can be converted to the corresponding amino acids by the catalytic action of an enzyme or the microbial cells as an enzyme source, t - Alanine production from L-aspartic acid, L-aspartic acid production from fumaric acid, L-cysteine production from DL-2-aminothiazoline-4-catboxyhc acid, D-phenylglycine (and D-/> -hydtoxyphenylglycine) production from DL-phenyUiydantoin (and DL-/)-hydroxyphenylhydantoin), and L-tryptophan production from indole and DL-serine have been in operation as commercial processes. Some of the other processes shown in Table 10 are at a technical level high enough to be useful for commercial production (24). Representative chemical reactions used ia the enzymatic process are shown ia Figure 6. 

Gilles, E. D. Kremling, A. Metabolic design based on a coupled gene expression-metabolic network model of tryptophan production in Escherichia coli. Metab Eng... 

For tryptophan production in E. coli, the natural regulation controlling production of tyrosine and phenylalanine was sufficient to keep carbon flowing specifically to tryptophan. This eliminated the need for addition of auxotrophic compounds to the growth medium. The major industrial producers of tryptophan are ADM, Kwoya Hakko, and Ajinomoto. 

Figure 1 Biosynthesis of i-tryptophan. (Reproduced from Mayeno AN and Gleich GJ (1994) Eosinophilia-myalgia syndrome and tryptophan production A cautionary taie. Trends in Biotechnology 12 346-352, with permission from Elsevier.)...

Adachi, J., Mio, T., Ueno, Y., Naito, T., Nishimura, A., Fujiwara, S., Sumino, K., and Tatsuno, Y., Identification of four metabolites of 3-(phenylamino)alanine, a constituent in L-tryptophan products implicated in eosinophilia-myalgia syndrome, in rats, Arch. Toxicol., 68, 500, 1994. 

Mayeno, A. N. and Gleich, G. J., Eosinophilia-myalgia syndrome and tryptophan production A cautionary tale, Trends Biotechnol., 12, 346, 1994. 

Previous work, on the use of a reverse-micelle system for the production of tryptophan reported kinetic data obtained under various conditions (2). Both the water-to-surfactant ratio and the cosurfactant used influenced tryptophan production. The present work reports results from EPR studies of the effect of these parameters on both the water and the enzyme in the reverse micelle. EPR spectra of Mn(H20)g + were recorded to investigate the state of the water in reverse micelles. A nitroxide spin label that reacts with lysine residues was employed to probe the microstructure of tryptophanase in reverse micelles of different w0 values. 

Results and Discussion. Kinetic studies have shown that tryptophan production in reverse micelles is senstitive to w0 and hence to micelle size Q). Figure 4 shows the effect of w0 on tryptophan production. Tryptophanase exhibited its highest activity at a w0 of about 20. 

Starting Molecule N-Methyl-L-tryptophan Product N-Methyl-tryptamine... 

For the tryptophan pathway it is a matter of debate whether there is only one pathway that is localized in the plastids, or whether a plastidial and cytosolic pathway occurs in the plant. In the latter hypothesis, the cytosolic pathway is believed to be responsible for the secondary metabolism, whereas the plastidial pathway takes care of the tryptophan production for primary metabolism (for a review, see ref. 143). So far no evidence for such a dual pathway has been found in C. roseus (156 R. Bongaerts et al., unpublished results). 

Schallenberg and Berlin (27) selected several 5-methyltryptophan-resistant cell lines from wild-type cells of different C. roseus cell suspension cultures. This resulted in increased tryptophan synthesis in all cell lines, and up to 30 times the normal levels of free tryptophan were detected. Increased tryptophan production did not, however, result in higher levels of tryptamine nor indole alkaloids. 

Zhao, Z.-J. et al (2011) Development of L-tryptophan production strains by defined genetic modification in Escherichia coll J. Ind. Microbiol Biotechnol, 38, 1921—1929. 

Aiba, S., Tsunekawa, H., Imanaka, T. New Approach to Tryptophan Production by Escherichia coli Genetic Manipulation of Composite Plasmids in tro Appl. Environm. Microbiol., 43, 289 (1982)... 

Ujimaru, T., Kakimoto, T., Chibata, I. L-Tryptophan Production by Achromobacter liquidum Appl. Environm. Microbiol., 46,1 (1983)... 

Gu P, KangJ.Yang F, Wang Q, Liang Q, Qi Q.The improved 1-tryptophan production in recombinant Escherichia coli by expressing the polyhydroxybutyrate synthesis pathway. Appl Microbiol Biotechnol 2013 97 4121-7. 

Reported adverse events from acute and chronic high-level intakes of AAs are extremely rare. A notable exception is the observation of a potential link between tryptophan and EMS dining the late 1980s and early 1990s. At that time, the U S. Food and Drug Administration banned the sale of tryptophan products in the U S. It has since been generally accepted that the cause of this problem was not the tryptophan itself, but a contaminated batch that led to the disease in users. 

Similar reactions transform DL-5-monosubstituted hydantoins to L-amino acids. Yo-kozeki et al. [11] analyzed the reaction mechanism of L-tryptophan production from dl-5-(3 -indolylmethyl)hydantoin by Flavobacterium sp. and found that nonstereospecific hydrolysis of hydantoin derivative and the L-sj ific hydrolysis of racemic A-carbamoyl amino acid were involved in this transformation. Yamashiro et al. [12] found the L-specific hydrolysis of a hydantoin derivative in L-valine production firom DL-5-isopropylhydantoin by Bacillus sp. and that ATP was absolutely required for this amidohydrolytic reaction. 

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