Figure 2.

Investigation of STS inhibition reversibility of selected 13β-estrone compounds 7a, 16c. Inhibitor compounds were preincubated with human placental microsomes for 10 and 20 min. Following a 50-fold dilution step and 20 min secondary incubation to allow dissociation, the usual enzyme activity measurement was applied. Mean ± SD of three separate experiments. Experimental conditions: I No preincubation, 7a 0.03 μM; 16c 0.2 μM, II No preincubation, 7a 1.5 μM; 16c 10 μM, III Preincubation, 2.5 min, 7a 1.5 μM; 16c 10 μM, IV Preincubation, 10 min, 7a 1.5 μM; 16c 10 μM, V Preincubation, 20 min, 7a 1.5 μM; 16c 10 μM.