Abstract:Insect cytochrome P450 is a kind of gene family that plays important roles in biological metabolism and performs many important physiological functions, including the plant secondary metabolism and insect resistance to insecticides. In this study, total RNA sample of five instar Ostrinia furnacalis larvae midgud was used as template, a pair of degenerate primers were designed based on the reported sequences of conservative amino acid regions of P450 protein family in insects. The cDNA encoding the cytochrome P450 protein was isolated from the five instar Ostrinia furnacalis larva midgut by reverse transcription polymerase chain reaction (RT-PCR) and RACE technology.The complete cDNA fragment was cloned into vector pMD19-T. Sequnence analysis showed that the full-length of Ostrinia furnacalis P450 (GenBank accession no. EU807990) was 2315 bp, encoding 523 amino acid residues. The sequence of OfP450 is named as CYP6AE25 by the International P450 Nomenclature Committee. The research made a more detailed analysis and forecast for CYP6AE25 from the aspects of physical and chemical properties, composition, signal peptide, transmembrane domain, secondary structure, tertiary structure and functional structure domain.It provides a theoretical basis to study between the relationship structure and function. Molecular evolutionary tree analysis revealed that CYP6AE25 protein and other insect family P450 have higher homology, compared with the other CYP family, farther genetic distance, less homologous.