Proteus mirabilis dehydrogenates aldonates and aldarates with an (R)-configured alpha-carbon atom to the corresponding 2-oxocarboxylates.
Resting cells of Proteus mirabilis effectively dehydrogenate aldonates and aldarates to the corresponding 2-oxocarboxylates (Figure 2). The prerequisite is an (R)-configured alpha-carbon atom next to the carboxylate group. The oxidation reagent is dimethylsulfoxide and the electron mediator is anthraquinone-2,6-disulfonate (Figure 1). The reactions mostly proceed quantitatively in concentrations up to 0.5 M. The two enzymes necessary for the dehydrogenation, (2R)-hydroxycarboxylate viologen oxidoreductase and dimethylsulfoxide reductase, are present in P. mirabilis in high activities. Nine aldonates have been dehydrogenated to 2-glyculosonates (2-oxoaldonates) and two aldarates to alpha-oxo aldarates. As shown with lactobionate and 6-phospho-D-gluconate, derivatives of aldonates can be dehydrogenated too. The apparent Km values of the substrates are often < 1 mM. The products were isolated as sodium or potassium salts with yields between 65 and 98% and characterized. D-xylo-Hex-2-ulosonate obtained from D-gulonate was converted to D-ascorbic acid.
Schinschel
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Institute of Organic Chemistry, Technische Universität München, Garching, Germany.
Simon
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D001426:Bacterial Proteins; D001711:Biotransformation; D002236:Carbohydrate Conformation; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D007506:Iron-Sulfur Proteins; D007651:Keto Acids / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009904:Optical Rotation; D010088:Oxidoreductases / Q000378:metabolism*; D011513:Proteus mirabilis / Q000201:enzymology*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013400:Sugar Acids / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D002241:Carbohydrates; D007506:Iron-Sulfur Proteins; D007651:Keto Acids; D013400:Sugar Acids; D010088:Oxidoreductases; C088331:HVOR protein, Proteus vulgaris; C045664:dimethyl sulfoxide reductase