NADH-dependent flavin oxidoreductase (PubMed:8491719, PubMed:7599167, PubMed:18047844). Stereo-specific NAD(H)-dependent 3-oxo-delta4-cholenoic acid oxidoreductase involved in bile acid 7beta-dehydroxylation (PubMed:18047844). 7beta-hydroxy-3-oxochol-24-oyl-CoA + NAD(+) = 7beta-hydroxy-3-oxochol-4-en-24-oyl-CoA + H(+) + NADH Activity is inhibited by sulfhydryl-reactive compounds, acriflavine, o-phenanthroline and EDTA. Lipid metabolism; bile acid degradation. Homotrimer. Induced by cholate. In the N-terminal section; belongs to the NADH:flavin oxidoreductase/NADH oxidase family.