@article{oai:kanazawa-u.repo.nii.ac.jp:00010337,
 author = {板垣, 英治 and Hatta, Takashi and Wakabayashi, Teruko and Itagaki, Eiji},
 issue = {4},
 journal = {Journal of Biochemistry},
 month = {Jan},
 note = {The inducible 3-keto-5α-steroid-Δ4-dehydrogenase of Nocardia corallina was purified to homogeneity using affinity chromatography on 19-nortestosterone-17-acetoxyaminoethyl Sepharose 4B. SDS-polyacrylamide gel electrophoresis, gel filtration and spectral analysis of flavin suggest that the purified dehydrogenase is a monomeric protein of M(r) 60,000 containing one flavin. It has a typical absorption spectrum of flavoprotein with maxima at 457, 375, and 277 nm. The values shifted to 470 and 395 nm on binding of 19-nortestosterone. The enzyme catalyzed the dehydrogenation of 3-keto-5α-steroid at the 4- and 5-position, e.g. the conversion of 5α-androst-1-ene-3,17-dione to 1,4-androstadiene-3,17-dione with the reduction of phenazine methosulfate. The substrate 3-ketosteroid has essentially the 5α-configuration. The enzyme did not reduce potassium ferricyanide but did reduce cytochrome c at a moderate rate, and exhibited only a weak steroid oxidase activity. Stereochemical study demonstrated that the enzyme abstracts the 4β, 5α-hydrogens of the substrate as a hydrogen ion through a protein-based reaction and as a hydride ion by transfer to FAD, respectively. The enzyme oxidizes a wide variety of 3-keto-5α-steroids but not 3β-hydroxysteroid. The dehydrogenase also catalyzed steroid transhydrogenation between 3-keto-5α-steroid and 3-keto-1,4-diene-steroid. The properties of this enzyme are compared with those of 3-keto-steroid-Δ1-dehydrogenase., 金沢大学自然科学研究科, 金沢大学理工研究域自然システム学系},
 pages = {581--586},
 title = {3-keto-5α-steroid-Δ4-dehydrogenase from Nocardia corallina: Purification and characterization},
 volume = {109},
 year = {1991}
}