- Source: 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione 4,5-dioxygenase
In enzymology, a 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione 4,5-dioxygenase (EC 1.13.11.25) is an enzyme that catalyzes the chemical reaction
3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione + O2
⇌
{\displaystyle \rightleftharpoons }
3-hydroxy-5,9,17-trioxo-4,5:9,10-disecoandrosta-1(10),2-dien-4-oate
Thus, the two substrates of this enzyme are 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione and O2, whereas its product is 3-hydroxy-5,9,17-trioxo-4,5:9,10-disecoandrosta-1(10),2-dien-4-oate.
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. The systematic name of this enzyme class is 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione:oxygen 4,5-oxidoreductase (decyclizing). Other names in common use include steroid 4,5-dioxygenase, and 3-alkylcatechol 2,3-dioxygenase. It employs one cofactor, iron.
References
Gibson DT, Wang KC, Sih CJ, Whitlock H (February 1966). "Mechanisms of steroid oxidation by microorganisms. IX. On the mechanism of ring A cleavage in the degradation of 9,10-seco steroids by microorganisms". The Journal of Biological Chemistry. 241 (3): 551–9. PMID 5908121.