EC 5.3.1.21     
Accepted name: corticosteroid side-chain-isomerase
Reaction: 11-deoxycorticosterone = 20-hydroxy-3-oxopregn-4-en-21-al
Systematic name: 11-deoxycorticosterone aldose-ketose-isomerase
Comments: An epimerization at C-20 and C-21 is probably catalysed by the same enzyme.
References:
1.  Martin, K.O., Oh, S.-W., Lee, H.J. and Monder, C. Studies on 21-3H-labeled corticosteroids: evidence for isomerization of the ketol side chain of 11-deoxycorticosterone by a hamster liver enzyme. Biochemistry 16 (1977) 3803–3809. [PMID: 901753]
2.  Monder, C., Martin, K.O. and Bogumil, J. Presence of epimerase activity in hamster liver corticosteroid side chain isomerase. J. Biol. Chem. 255 (1980) 7192–7198. [PMID: 7391077]
[EC 5.3.1.21 created 1983]