Enzymatic preparation of L‐tryptophan and 5‐hydroxy‐L‐tryptophan

Nakazawa, Hidetsugu; Enei, Hitoshi; Okumura, Susumu

doi:10.1016/0014-5793(72)80449-6

Cited by 53 publications

(9 citation statements)

References 12 publications

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“…During the production of 5-HTP, the endogenous metabolic enzymes of E. coli (e.g., tryptophanase) degrade l -tryptophan to indole, pyruvate, and ammonia; and 5-HTP is degraded to 5-hydroxyindole, pyruvate, and ammonia (Nakazawa et al 1972a; Nakazawa et al 1972b; Watanabe and Snell 1972). We also confirmed the degradation of 5-HTP as well as of l -tryptophan in the wild-type E. coli whole cell reaction (Figure 1), and then attempted to delete the gene encoding tryptophanase ( tnaA ), which is the enzyme that initially degrades l -tryptophan, to overcome these drawbacks.…”

Section: Resultsmentioning

confidence: 99%

Enhanced synthesis of 5-hydroxy-l-tryptophan through tetrahydropterin regeneration

Kino

2013

AMB Express

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5-Hydroxy-l-tryptophan (5-HTP) is a naturally occurring aromatic amino acid present in the seeds of the African plant Griffonia simplicifolia. Although 5-HTP has therapeutic effects in various symptoms, efficient method of producing 5-HTP has not been established. In this study, we developed a novel cofactor regeneration process to achieve enhanced synthesis of 5-HTP by using modified l-phenylalanine 4-hydroxylase of Chromobacterium violaceum. For the synthesis of 5-HTP using Escherichia coli whole cell bioconversion, l-tryptophan and 5-HTP degradation by E. coli endogenous catabolic enzymes should be considered. The tryptophanase gene was disrupted using the λ red recombination system, since tryptophanase is postulated as an initial enzyme for the degradation of l-tryptophan and 5-HTP in E. coli. For regeneration of the cofactor pterin, we screened and investigated several key enzymes, including dihydropteridine reductase from E. coli, glucose dehydrogenase from Bacillus subtilis, and pterin-4α-carbinolamine dehydratase from Pseudomonas syringae. Genes encoding these three enzymes were overexpressed in an E. coli tryptophanase-deficient host, resulting in the synthesis of 0.74 mM 5-HTP in the presence of 0.1 mM pterin and the synthesis of 0.07 mM 5-HTP in the absence of regeneration of pterin. These results clearly indicated the successful regeneration of pterin. Following optimization of the reaction conditions, 2.5 mM 5-HTP was synthesized with cofactor regeneration, while 0.8 mM 5-HTP was recovered without cofactor regeneration under the same reaction conditions, suggesting that the principle described here provides a new method for cofactor regeneration.

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Section: Resultsmentioning

confidence: 99%

Enhanced synthesis of 5-hydroxy-l-tryptophan through tetrahydropterin regeneration

Kino

2013

AMB Express

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“…5). When such a high concentration of Ltryptophan accumulated, it precipitated in the reaction mixture without the addition of precipitant (9,10).…”

Section: Resultsmentioning

confidence: 99%

l -Tryptophan Production by Achromobacter liquidum

Ujimaru

Kakimoto

Chibata

1983

Appl Environ Microbiol

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Conditions for the production of tryptophanase from Achromobacter liquidum and for the conversion of L-serine and indole to L-tryptophan were studied. The enzyme could be produced in amnounts as great as 0.750 U/ml (degradation) and 0.294 U/ml (synthesis) by shaking cultures at 30°C in a medium containing dextrin, yeast extract, L-tryptophan, and L-glutamic acid. L-Tryptophan was produced most efficiently by shaking the cells at 37°C in a reaction mixture containing 60 mg of L-serine per ml, 60 mg of indole per ml, and 0.5 mM pyridoxal phosphate. After 3 days, 96 mg of L-tryptophan per ml was formed, and L-tryptophan was easily isolated to 85.4% yield by concentration of the reaction mixture.

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“…The tryptophan accumulating as a precipitate in the reaction mixture was isolated and purified according to Nakazawa et al (1972). The optical activity of tryptophan was analysed by a polarimeter (model DIP-380, Japan Spectroscopic, Tokyo, Japan).…”

Section: Formation Of Tryptophan By the Cell Harbouring Pbr322f-patsmentioning

confidence: 99%

Application of the tryptophanase promoter to high expression of the tryptophan synthase gene inEscherichia coli

Terasawa

Inui²,

Uchida³

et al. 1991

Appl Microbiol Biotechnol

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The application of an inducible regulation system using the tryptophanase operon promoter (TPase promoter; Ptna) was examined for its high expression of the tryptophan synthase (TS) gene in Escherichia coli. The main problem in the application of Ptna for industrial purposes is catabolite repression by glucose, since glucose is the most abundant carbon source. However, this problem could be avoided by changing glucose to an organic acid, such as succinate, fumarate, malate and acetate, in the course of cultivation after glucose initially added was completely consumed. Under these conditions, L-tryptophan was also used to induce tryptophan synthase. Thus, the specific activity of TS in E. coli strain no. 168 harbouring pBR322F-Ptna TS was increased 500-fold compared to that of the cultured host strain. About 1 mol L-tryptophan/l reaction mixture was formed from indole and L-serine at 37 degrees C for 3.5 h.

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Enzymatic preparation of L‐tryptophan and 5‐hydroxy‐L‐tryptophan

Cited by 53 publications

References 12 publications

Enhanced synthesis of 5-hydroxy-l-tryptophan through tetrahydropterin regeneration

Enhanced synthesis of 5-hydroxy-l-tryptophan through tetrahydropterin regeneration

l -Tryptophan Production by Achromobacter liquidum

Application of the tryptophanase promoter to high expression of the tryptophan synthase gene inEscherichia coli

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