Purification and properties of NAD(P)-independent polyol dehydrogenase complex from the plasma membrane ofGluconobacter oxydans

2007 ◽  
Vol 53 (4) ◽  
pp. 504-508 ◽  
Author(s):  
Ian J. VanLare ◽  
G.W. Claus
Keyword(s):  
Electron Transport Chain ◽  
Gluconobacter Oxydans ◽  
Hydroxyl Groups ◽  
Polyol Dehydrogenase ◽  
Transport Chain ◽  
Purification And Properties ◽  
Catalytic Unit ◽  
Membrane Bound ◽  
Cyclic Alcohols ◽  
Dehydrogenase Complex

Gluconobacter oxydans rapidly oxidizes many different polyhydroxy alcohols (polyols). Polyol oxidations are catalyzed by constitutively synthesized membrane-bound dehydrogenases directly linked to the electron transport chain. A polyol-oxidizing enzyme was isolated from the membranes of G. oxydans and tested for its ability to oxidize various substrates. The enzyme was composed of three subunits: a 67 kDa catalytic unit, a 46 kDa c-type cytochrome, and a 15 kDa subunit. The enzyme oxidized compounds containing three or more hydroxyl groups but did not oxidize mono-, di-, or cyclic alcohols; aldehydes; carboxylic acids; or mono- or di-saccharides. Therefore, we propose this enzyme be considered a polyol dehydrogenase.

scholarly journals Characterization and inactivation of the membrane-bound polyol dehydrogenase in Gluconobacter oxydans DSM 7145 reveals a role in meso-erythritol oxidation

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1890-1899 ◽  
Author(s):  
Jörn Voss ◽  
Armin Ehrenreich ◽  
Wolfgang Liebl
Keyword(s):  
Acetic Acid ◽  
Gluconobacter Oxydans ◽  
Acetic Acid Bacteria ◽  
Second Phase ◽  
Growth Substrate ◽  
Whole Cell ◽  
Polyol Dehydrogenase ◽  
Membrane Bound ◽  
Two Stages ◽  
Substrate Spectrum

The growth of Gluconobacter oxydans DSM 7145 on meso-erythritol is characterized by two stages: in the first stage, meso-erythritol is oxidized almost stoichiometrically to l-erythrulose according to the Bertrand–Hudson rule. The second phase is distinguished from the first phase by a global metabolic change from membrane-bound meso-erythritol oxidation to l-erythrulose assimilation with concomitant accumulation of acetic acid. The membrane-associated erythritol-oxidizing enzyme was found to be encoded by a gene homologous to sldA known from other species of acetic acid bacteria. Disruption of this gene in the genome of G. oxydans DSM 7145 revealed that the membrane-bound polyol dehydrogenase not only oxidizes meso-erythritol but also has a broader substrate spectrum which includes C3–C6 polyols and d-gluconate and supports growth on these substrates. Cultivation of G. oxydans DSM 7145 on different substrates indicated that expression of the polyol dehydrogenase was not regulated, implying that the production of biomass of G. oxydans to be used as whole-cell biocatalysts in the biotechnological conversion of meso-erythritol to l-erythrulose, which is used as a tanning agent in the cosmetics industry, can be conveniently carried out with glucose as the growth substrate.

Ferrous iron oxidation in moderately thermophilic acidophile Sulfobacillus sibiricus N1T

2010 ◽  
Vol 56 (10) ◽  
pp. 803-808 ◽  
Author(s):  
Tatiana Y. Dinarieva ◽  
Anna E. Zhuravleva ◽  
Oksana A. Pavlenko ◽  
Iraida A. Tsaplina ◽  
Alexander I. Netrusov
Keyword(s):  
Ferrous Iron ◽  
High Performance ◽  
Iron Oxidation ◽  
Early Exponential Phase ◽  
Moderately Thermophilic ◽  
Terminal Oxidases ◽  
Cytochrome Bo ◽  
Ferrous Iron Oxidation ◽  
Transport Chain ◽  
Membrane Bound

The iron-oxidizing system of a moderately thermophilic, extremely acidophilic, gram-positive mixotroph, Sulfobacillus sibiricus N1T, was studied by spectroscopic, high-performance liquid chromatography and inhibitory analyses. Hemes B, A, and O were detected in membranes of S. sibiricus N1T. It is proposed that the electron transport chain from Fe2+ to O2 is terminated by 2 physiological oxidases: aa3-type cytochrome, which dominates in the early-exponential phase of growth, and bo3-type cytochrome, whose role in iron oxidation becomes more prominent upon growth of the culture. Both oxidases were sensitive to cyanide and azide. Cytochrome aa3 was more sensitive to cyanide and azide, with Ki values of 4.1 and 2.5 µmol·L–1, respectively, compared with Ki values for cytochrome bo3, which were 9.5 µmol·L–1 for cyanide and 7.0 µmol·L–1 for azide. This is the first evidence for the participation of a bo3-type oxidase in ferrous iron oxidation. The respiratory chain of the mixotroph contains, in addition to the 2 terminal oxidases, a membrane-bound cytochrome b573.

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