Purification and Some Properties of an Extracellular 3β-Hydroxysteroid Oxidase Produced by Corynebacterium cholesterolicum

概要

論文の詳細を見る
A new type of 3β-hydroxysteroid oxidase was purified from the culture filtrate of a Corynebacterium sp. (C. cholesterolicum ATCC 31216) and some properties were investigated.The enzyme showed optimum activity at pH 7.0〜7.5 and was stable at pH 5〜9. Various 3β-hydroxysteroids were oxidized and the relative oxidation rates were : cholesterol, 100; β-sitosterol, 50; pregnenolone, 38; stigmasterol, 12. The enzyme activity was markedly inhibited by nonionic detergents suc as Triton X-100,Tween 80,and Brij 35. The K_m values for oxidation of cholesterol in the presence of 0.002% (v/v) and 0.01% (v/v) Triton X-100 were 1.97 and 14.3 μM, respectively. Metal chelating reagents did not inhibit the enzyme.The molecular weight was estimatd to be 57,000 by SDS-polyacrylamide gel electrophoresis, and 58,000 by gel filtration in the presence of 6 M guanidine hydrochloride. The enzyme was proved to be a flavoprotein with 1 mole of flavin adenine dinucleotide per mole of protein. Amino acid analysis showed that the enzyme protein was composed of 451 amino acid residues including 36 moles of alanine and 9 moles of tryptophan.
公益社団法人日本生物工学会の論文
1977-08-25