Diol dehydratase of Lactobacillus diolivorans was purified by ammonium sulfate precipitation and gel filtration chromatography.The molecular mass of the native complex was estimated to be 200×103 by nondenaturing polyacrylamide gel electrophoresis.Three main bands were present after SDS-PAGE with molecular masses of 62×103

35×103 and 22×103

respectively. Km for the three main substrates were 1.3 mmol·L-1 for 1

2-propanediol，5.8 mmol·L-1 for glycerol and 10.3 mmol·L-1 for 1

2-ethanediol.Km for adenosylcobalamin coenzyme was 1.5 μmol·L-1

which was required for the enzyme catalysis.The optimal reaction conditions of the enzyme were pH 8.6 and 37℃.