Propanediol dehydrase

Protein-chemical Properties of Apoenzyme. Adenosylcobalamin-dependent diol dehydrase was discovered and isolated first by Abeles and co-workers (3, 4) in the cells of Klebsiella pneumoniae (formerly known as Aerohacter aero genes) ATCC 8724 grown without aeration in a glycerol or glycerol-1,2-propanediol medium. This enzyme catalyzes the conversion of 1,2-propanediol, 1,2-ethanediol, and glycerol to propionaldehyde, acetaldehyde, and j3-hydroxypropionaldehyde, respectively (4, 5). Adenosylcobalamin and K+ or other monovalent cations of a similar size are required for catalysis. Recently, the au-... 

Figure 4. Affinity chromatography of diol dehydrase on the adenosyl form of II (37). About 1 unit of enzyme was applied to 1 mL of packed corrinoid gel in 0.1 M potassium phosphate buffer (pH 8.0) containing 2% 1,2-propanediol, in a total volume of 2 mL. Affinity chromatography was carried out as described in the text. Two-milliliter fractions...

Valinsky, J. E., Abeles, R. H., and Eee, J. A., 1974, Electron spin resonance studies on diol dehydrase. III. Rapid kinetic studies on the rate of formation of radicals in the reaction with propanediol, J. Am. Chem. Soc. 96 4709n4710. 

Co—C bond cleavage, but is consistent with either homolysis or heterolysis. Diol dehydrase gives inversion at the C-2 carbon when 1,2-propanediol is the substrate, and glutamate mutase also gives inversion. The reactions of methylmalonyl-CoA mutase and ribonucleotide triphosphate reductase proceed with retention. This stereospecificity indicates that the reacting carbon center of the substrate does not pass through a planar intermediate. 

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