Effect of bromocriptine on the kinetics of reduction of the total pool (a) and the high-spin fraction (b) of CYP3A4 in the oligomers in solution. The kinetic curves were recorded at no substrate added (circles) and in the presence of 1 μM (squares) and 6 μM (diamonds) bromocriptine. The data are plotted in semilogarithmic coordinates. Lines show the results of fitting of the data to the equation of sum of three (a) or two (b) exponents. Conditions: 3 μM 3A4, 12.5 mM sodium dithionite, CO-saturated 0.1 M Na-Hepes buffer, pH 7.4, 1 mM DTT, 1 mM EDTA, 25 °C.