title: Biotransformation of D-methionine into L-methionine in the cascade of four enzymes.
abstract: D-Methionine was converted to L-methionine in a reaction system where four enzymes were used. D-amino acid oxidase (D-AAO) from Arthrobacter protophormiae was used for the complete conversion of D-methionine to 2-oxo-4-methylthiobutyric acid. Catalase was added to prevent 2-oxo-4-methylthiobutyric acid decarboxylation. In the second reaction step, L-phenylalanine dehydrogenase (L-PheDH) from Rhodococcus sp. was used to convert 2- oxo-4-methylthiobutyric acid to L-methionine, and formate dehydrogenase (FDH) from Candida boidinii was added for NADH regeneration. Enzyme kinetics of all enzymes was analyzed in detail. Mathematical models for separate reactions steps, as well as for the complete system were developed and validated in the batch reactor experiments. Complete conversion of D-methionine to L-methionine was achieved. Considering that both enzymes act on different substrates, such a system could be easily employed for the synthesis of other amino acids from D-isomer, as well as from the racemate of a certain amino acid (DL-amino acid).
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Savska c. 16, HR-10 000 Zagreb, Croatia.
authors.forename: Z
authors.initials: Z
authors.lastname: Findrik
authors.forename: D
authors.initials: D
authors.lastname: Vasić-Racki
mesh_terms: D000465:Algorithms; D000594:Amino Acid Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001173:Arthrobacter / Q000201:enzymology; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D001711:Biotransformation; D002175:Candida / Q000201:enzymology; D002374:Catalase / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D002417:Cattle; D003605:D-Amino-Acid Oxidase / Q000737:chemistry* / Q000378:metabolism; D005560:Formate Dehydrogenases / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008715:Methionine / Q000031:analogs & derivatives / Q000737:chemistry* / Q000378:metabolism; D008956:Models, Chemical; D009243:NAD / Q000737:chemistry / Q000378:metabolism; D012240:Rhodococcus / Q000201:enzymology; D013237:Stereoisomerism
chemical_list: D009243:NAD; C014632:2-keto-4-methylthiobutyric acid; D008715:Methionine; D002374:Catalase; D005560:Formate Dehydrogenases; D000594:Amino Acid Oxidoreductases; C022342:phenylalanine oxidase; D003605:D-Amino-Acid Oxidase