Streptolysin o from streptococcus pyogenes

In our study, we used human recombinant CYP3A4 (142 µM CYP3A4 in 550 mM potassium phosphate buffer (pH 7.2), containing 0.2% CHAPS, 1 mM dithiothreitol and 20% glycerol (v/v)). This enzyme was purified according to a published earlier protocol [30 (link)] in the Institute of Bioorganic Chemistry (Minsk, Belarus). The concentration of CYP3A4 was determined by a complex formation of a reduced form with carbon monoxide using the absorption coefficient ɛ₄₅₀= 91 mM⁻¹ cm⁻¹ [31 (link)]. Acetylacetone was purchased from Fluka (Switzerland). Potassium hydroxide, potassium dihydrogen phosphate, sodium chloride were purchased from Spectrchem (Moscow, Russia). Acetic acid was purchased from Fisher Scientific (USA). Chemical reagents such as ammonium acetate, erythromycin, chloroform, didodecyldimethylammonium bromide (DDAB), disodium phosphate, DL-dithiothreitol, K₃[Fe(CN)₆]/K₄[Fe(CN)₆] and streptolysin O from Streptococcus pyogenes were purchased from Sigma-Aldrich (St. Louis, MO, USA).