Thinking beyond detoxification

The cytochrome P450-dependent monooxygenases are an extremely important metabolic system involved in the metabolism of xenobiotics and endogenous compounds. The number of P450s in a given insect species currently ranges from 48 in Apis mellifera to 164 in Aedes aegypti. For nearly forty years studies of insect P450s have focused primarily on metabolism of xenobiotics, including studies of insecticide resistance, insecticide metabolism and insect-plant interactions. This has led to the perception, held by at least some in the scientific community, that the majority of P450s in a given species are primarily for detoxification of xenobiotics. However, there are an Correspondence/Reprint request: Dr. Jeffrey G. Scott, Department of Entomology, Comstock Hall, Cornell University, Ithaca, NY 14853-0901, USA. E-mail: [email protected] Jefferey G. Scott 118 ever increasing number of studies that indicate P450s have a much broader role in insects. Herein, it is postulated that metabolism of xenobiotics might be the role for only a minority of the P450s in a given insect species. Examples of P450 metabolism (known and predicted) of compounds that are not xenobiotics are presented.