title: Reverse reaction of malic enzyme for HCO3- fixation into pyruvic acid to synthesize L-malic acid with enzymatic coenzyme regeneration.
abstract: Malic enzyme [L-malate: NAD(P)(+) oxidoreductase (EC 1.1.1.39)] catalyzes the oxidative decarboxylation of L-malic acid to produce pyruvic acid using the oxidized form of NAD(P) (NAD(P)(+)). We used a reverse reaction of the malic enzyme of Pseudomonas diminuta IFO 13182 for HCO(3)(-) fixation into pyruvic acid to produce L-malic acid with coenzyme (NADH) generation. Glucose-6-phosphate dehydrogenase (EC1.1.1.49) of Leuconostoc mesenteroides was suitable for coenzyme regeneration. Optimum conditions for the carboxylation of pyruvic acid were examined, including pyruvic acid, NAD(+), and both malic enzyme and glucose-6-phosphate dehydrogenase concentrations. Under optimal conditions, the ratio of HCO(3)(-) and pyruvic acid to malic acid was about 38% after 24 h of incubation at 30 degrees C, and the concentration of the accumulated L-malic acid in the reaction mixture was 38 mM. The malic enzyme reverse reaction was also carried out by the conjugated redox enzyme reaction with water-soluble polymer-bound NAD(+).
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ohno
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Nakamori
authors.forename: Haitao
authors.initials: H
authors.lastname: Zheng
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Suye
mesh_terms: D000464:Alginates / Q000737:chemistry / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000737:chemistry / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D008293:Malates / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000201:enzymology*; D019289:Pyruvic Acid / Q000378:metabolism*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D008293:Malates; D009243:NAD; D002245:Carbon Dioxide; C030298:malic acid; D019289:Pyruvic Acid; D020723:Glucuronic Acid; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+); D005954:Glucosephosphate Dehydrogenase