title: A Novel Type of D-Mannitol Dehydrogenase from Acetobacter xylinum: Occurrence, Purification, and Basic Properties.
abstract: We purified a novel type of D-mannitol dehydrogenase, which contains a c-type cytochrome and an unknown chromophore in the soluble fraction of an acetic acid bacterium, Acetobacter xylinum KU-1, to homogeneity. The enzyme showed the maximum activity at pH 5 and 40°C. It was stable up to 60°C at pH 6, and was inhibited by Hg(2+) and p-quinone (Ki = 0.18 mm). The molecular weight of the enzyme was about 140,000, and those of the subunits were 69,000, 51,000, and 20,000; the enzyme is hetero-trimeric and contained 8 g-atoms of Fe per mole. The α-helix content was estimated to be about 52.9%. The enzyme catalyzed phenazine methosulfate dependent oxidation of d-mannitol with an apparent Km of 98 μm (for d-mannitol) and Vmax of 213 μmol/min/mg. The reduced form of the enzyme showed the absorption maxima at 386, 416, 480, 518, 550, and 586 nm, which are attributable to a c-type cytochrome in the enzyme.
authors.affiliation: a Department of Biotechnology, Faculty of Engineering , Kansai University.|b Kansai University High Technology Research Center , Suita-shi, Osaka 564 , Japan.
authors.forename: T
authors.initials: T
authors.lastname: Oikawa
authors.affiliation: a Department of Biotechnology, Faculty of Engineering , Kansai University.
authors.forename: J
authors.initials: J
authors.lastname: Nakai
authors.affiliation: a Department of Biotechnology, Faculty of Engineering , Kansai University.
authors.forename: Y
authors.initials: Y
authors.lastname: Tsukagawa
authors.affiliation: a Department of Biotechnology, Faculty of Engineering , Kansai University.|b Kansai University High Technology Research Center , Suita-shi, Osaka 564 , Japan.
authors.forename: K
authors.initials: K
authors.lastname: Soda
keywords: Acetobacter xylinum; D-mannitol dehydrogenase; c-type cytochrome