EC - Steroid C-25 hydroxylase

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IntEnz Enzyme Nomenclature


Accepted name:
steroid C-25 hydroxylase
Other names:
cholesterol C-25 dehydrogenase
steroid C-25 dehydrogenase
Systematic name:
cholest-4-en-3-one:acceptor oxidoreductase (25-hydroxylating)



The enzyme, characterized from the bacterium Sterolibacterium denitrificans, participates in the anaerobic degradation of cholesterol. The enzyme can accept several substrates including vitamin D3. The enzyme contains a bis(guanylyl molybdopterin) cofactor, five [Fe-S] clusters, and one heme b. cf. EC, cholesterol 25-monooxygenase, an oxygen-requiring eukaryotic enzyme that catalyses a similar transformation.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Dermer, J., Fuchs, G.
    Molybdoenzyme that catalyzes the anaerobic hydroxylation of a tertiary carbon atom in the side chain of cholesterol.
    J Biol Chem 287 : 36905-36916 (2012). [PMID: 22942275]
  2. Rugor, A., Tataruch, M., Staron, J., Dudzik, A., Niedzialkowska, E., Nowak, P., Hogendorf, A., Michalik-Zym, A., Napruszewska, D. B., Jarzebski, A., Szyma?ska, K., Bialas, W., Szaleniec, M.
    Regioselective hydroxylation of cholecalciferol, cholesterol and other sterol derivatives by steroid C25 dehydrogenase.
    Appl Microbiol Biotechnol 101 : 1163-1174 (2017). [PMID: 27726023]
  3. Rugor, A., Wojcik-Augustyn, A., Niedzialkowska, E., Mordalski, S., Staron, J., Bojarski, A., Szaleniec, M.
    Reaction mechanism of sterol hydroxylation by steroid C25 dehydrogenase - Homology model, reactivity and isoenzymatic diversity.
    J Inorg Biochem 173 : 28-43 (2017). [PMID: 28482186]
  4. Jacoby, C., Eipper, J., Warnke, M., Tiedt, O., Mergelsberg, M., Stark, H.J., Daus, B., Martin-Moldes, Z., Zamarro, M.T., Diaz, E. and Boll, M.
    Four molybdenum-dependent steroid C-25 hydroxylases: Heterologous overproduction, role in steroid degradation, and application for 25-hydroxyvitamin D3 synthesis.
    mBIO 9 (2018). [PMID: 29921665]

[EC created 2020]