HPLC profiles of reactions catalyzed by CYP11B1 (A and C) and CYP11B2 (B and D) using DOC as substrate. Ratio cytochrome P450:substrate, 0.25:100 [the reaction time used: 0 min (blue) and 5 min (red)] (A and B). Ratio cytochrome P450:substrate, 1:20 [the reaction time used: 0 min (blue) and 30 min (red)] (C and D). 1, DOC; 2, B; 3, 18-hydroxy-DOC; 4, 18OH-B; 5, aldosterone.