PT - JOURNAL ARTICLE AU - Xiao, Yi AU - Shinkyo, Raku AU - Guengerich, F. Peter TI - Cytochrome P450 2S1 is Reduced by NADPH-Cytochrome P450 Reductase AID - 10.1124/dmd.111.039321 DP - 2011 Jun 01 TA - Drug Metabolism and Disposition PG - 944--946 VI - 39 IP - 6 4099 - http://dmd.aspetjournals.org/content/39/6/944.short 4100 - http://dmd.aspetjournals.org/content/39/6/944.full SO - Drug Metab Dispos2011 Jun 01; 39 AB - Cytochrome P450 (P450) 2S1 is one of the orphan P450s without a clear physiological function. Controversy has arisen as to whether it can interact with NADPH-P450 reductase and accept electrons. The reduction of 1,4-bis{[2-(dimethylamino-N-oxide)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione (AQ4N) by P450 2S1 was confirmed, and the NADPH consumption rates were measured aerobically and anaerobically in the absence and presence of the drug. The reduction kinetics of P450 2S1 were rapid, as measured by stopped-flow kinetics. These results confirm that P450 2S1 can be reduced by NADPH-P450 reductase and suggest normal mixed-function oxidase roles of P450 2S1 to be revealed.