Purification and characterization of cholesterol oxidase from Pseudomonas sp. and taxonomic study of the strain

초록

A cholesterol-oxidase-producing microorganism, strain COX629, isolated from soil was identified as Pseudomonas sp. The cholesterol oxidase produced by Pseudomonas sp. strain COX629 was purified 2400-fold to homogeneity in an overall yield of 60% from culture broth. The enzyme was a monomer with a molecular weight of 56 000, as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Sephadex G-150 gel column chromatography. The enzyme showed optimum activity at pH 7.0 and was stable over a rather wide pH range of 4.0 to 11.0. The enzyme showed a high substrate specificity for 3β-hydroxysteroids and the K<inf>m</inf> value for the oxidation of cholesterol by this enzyme was about 0.2 m M. A characteristic of the enzyme is marked stability at high temperature. © 1989 Springer-Verlag.