HUMAN AND RAT CYTOCHROME P450 ISOFORM SELECTIVITY WITHIN A PANEL OF FLUOROMETRIC SUBSTRATES

摘要: The advantages of fluorescence detection in enzyme assays (e.g. sensitivity, ease use, etc) are well-known. In this study we have examined the relative catalytic selectivity more than 25 rat or human cDNAexpressed cytochromes P450 toward a panel several fluorometric substrates. substrates were dibenzyl fluorescein (DBF), 7benzyloxyquinoline (BQ), 3-cyano-7-ethoxycoumarin (CEC), 3-cyano-7methoxycoumarin (CMC), 7-methoxy-4-trifluoromethylcoumarin (MFC), 3[2-(N, N-diethyl-N-methylamino)ethyl]-7-methoxy-4-methylcoumarin (AMMC), 3-[2-(N,N-diethyl-N-methylamino)ethyl]-7-methoxy-4trifluoromethylcoumarin (MeAMFC), resorufin benzyl ether (BzRes), and 7-benzyloxy-4-trifluoromethylcoumarin (BFC). Within each substrate, experimental conditions chosen based on those optimized for particular isoform interest CYP2D6 AMMC). For most substrates, multiple isoforms found to catalyze formation fluorescent product. However, among tested, CYP2D2 displayed high with AMMC CYP3A enzymes selective BQ BFC. All could dealkylate at least one substrate exception CYP2A1. profiles distinct. These data illustrate utility probes detecting activity liver microsomes P450. Introduction