Enzyme kinetics of aldosterone production by ASCE and ASWT in vitro. A) Dose response curves of aldosterone production catalysed by ASCE (open circles), ASWT (closed circles) and 11β-hydroxylase (grey circles) incubated with 11-deoxycorticosterone (DOC 0.18-30 μM) for 24 h. Data are expressed as the mean +/− S.E.M. of 5 independent trials. The apparent kinetic enzyme parameters obtained were Km = 1.191 μM and Vmax = 27.08 μM/24 h for ASCE and Km = 1.163 μM and Vmax = 36.98 μM/24 h for ASWT, and the area under curve for each of the enzyme activities (ANOVA and Mann–Whitney test, p = 0.3095) is shown within the graph. B) Cell viability of HEK-293 incubated with increasing doses of DOC (0.8-50 μM).