Reaction: androstenedione + reduced acceptor + O2 = testololactone + acceptor + H2O
Glossary: androstenedione = androst-4-ene-3,17-dione
testololactone = 3-oxo-13,17-secoandrost-4-eno-17,13-lactone
Other name(s): androstene-3,17-dione hydroxylase; androst-4-ene-3,17-dione 17-oxidoreductase; androst-4-ene-3,17-dione hydroxylase; androstenedione monooxygenase; 4-androstene-3,17-dione monooxygenase
Systematic name: androst-4-ene-3,17-dione-hydrogen-donor:oxygen oxidoreductase (13-hydroxylating, lactonizing)
Comments: Has a wide specificity. A single enzyme from the ascomycete Neonectria radicicola (EC 1.14.13.54 ketosteroid monooxygenase) catalyses both this reaction and that catalysed by EC 1.4.99.4 progesterone monooxygenase.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 37256-74-9
References:
1. Prairie, R.L. and Talalay, P. Enzymatic formation of testololactone. Biochemistry 2 (1963) 203-208.