title: Enzymatic synthesis oF L-tryptophan from D,L-2-amino-delta2-thiazoline-4-carboxylic acid and indole by Pseudomonas sp. TS1138 L-2-amino-delta2-thiazoline-4-carboxylic acid hydrolase, S-carbamyl-L-cysteine amidohydrolase, and Escherichia coli L-tryptophanase.
abstract: L-Tryptophan (L-Trp) is an essential amino acid. It is widely used in medical, health and food products, so a low-cost supply is needed. There are 4 methods for L-Trp production: chemical synthesis, extraction, enzymatic synthesis, and fermentation. In this study, we produced a recombinant bacterial strain pET-tnaA of Escherichia coli which has the L-tryptophanase gene. Using the pET-tnaA E. coli and the strain TS1138 of Pseudomonas sp., a one-pot enzymatic synthesis of L-Trp was developed. Pseudomonas sp. TS1138 was added to a solution of D,L-2-amino-delta2-thiazoline-4-carboxylic acid (DL-ATC) to convert it to L-cysteine (L-Cys). After concentration, E. coli BL21 (DE 3) cells including plasmid pET-tnaA, indole, and pyridoxal 5'-phosphate were added. At the optimum conditions, the conversion rates of DL-ATC and L-Cys were 95.4% and 92.1%, respectively. After purifying using macroporous resin S8 and NKA-II, 10.32 g of L-Trp of 98.3% purity was obtained. This study established methods for one-pot enzymatic synthesis and separation of L-Trp. This method of producing L-Trp is more environmentally sound than methods using chemical synthesis, and it lays the foundations for industrial production of L-Trp from DL-ATC and indole.
authors.affiliation: College of Pharmacy, Tianjin Key Laboratory of Molecular Drug Research, Nankai University, 300071 Tianjin, China.
authors.forename: J
authors.initials: J
authors.lastname: Du
authors.forename: J J
authors.initials: JJ
authors.lastname: Duan
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Hou
authors.forename: F
authors.initials: F
authors.lastname: Bai
authors.forename: N
authors.initials: N
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Bai
mesh_terms: D000581:Amidohydrolases; D002264:Carboxylic Acids / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003545:Cysteine / Q000031:analogs & derivatives / Q000096:biosynthesis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods*; D007211:Indoles / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods*; D010957:Plasmids; D011549:Pseudomonas / Q000201:enzymology* / Q000235:genetics; D013844:Thiazoles / Q000378:metabolism; D014364:Tryptophan / Q000096:biosynthesis; D014368:Tryptophanase / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D007211:Indoles; D013844:Thiazoles; C006894:S-carbamylcysteine; C030374:indole; D014364:Tryptophan; D000581:Amidohydrolases; D014368:Tryptophanase; D003545:Cysteine