IUBMB Enzyme Nomenclature


Accepted name: 3-oxo-Δ1-steroid hydratase/dehydrogenase

Reaction: a 3-oxo-Δ1-steroid + H2O + acceptor = a steroid 1,3-dione + reduced acceptor (overall reaction)
(1a) a 3-oxo-Δ1-steroid + H2O = a 1-hydroxy-3-oxo-steroid
(1b) a 1-hydroxy-3-oxo-steroid + acceptor = a steroid 1,3-dione + reduced acceptor

Glossary: Δ1-dihydrotestosterone = 17β-hydroxy-5α-androst-1-en-3-one

Other name(s): atcABC (gene names)

Systematic name: 3-oxo-Δ1-steroid:acceptor 1-oxidoreductase

Comments: A molybdenum enzyme. The enzyme, characterized from the bacterium Steroidobacter denitrificans, is involved in the anaetrobic degradation of steroids. It is specific to 3-oxo-Δ1-steroids such as androsta-1-ene-3,17-dione and Δ1-dihydrotestosterone and does not act on 3-oxo-Δ4-steroids.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Yang, F.C., Chen, Y.L., Tang, S.L., Yu, C.P., Wang, P.H., Ismail, W., Wang, C.H., Ding, J.Y., Yang, C.Y., Yang, C.Y. and Chiang, Y.R. Integrated multi-omics analyses reveal the biochemical mechanisms and phylogenetic relevance of anaerobic androgen biodegradation in the environment. ISME J. 10 (2016) 1967-1983. [PMID: 26872041]

[EC created 2020]

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