NADPH-Cytochrome P450 Reductase (P450R), or POR, is an essential component of the cytochrome P450 monooxygenase system of eukaryotic cells. P450R is anchored in the endoplasmic reticulum membrane with its catalytic domain residing in the cytosol. The protein is composed of four domains: an N-terminal FMN-binding domain, a connecting domain, and C-terminal FAD- and NADPH-binding domains. The flavoprotein P450R contains one molecule each of FMN and FAD, which are essential for the transfer of electrons from NADPH to the P450 cytochromes. This reduction is necessary for cytochromes P450 to perform each cycle of oxidation. P450R plays a vital role in metabolism and detoxification of xenobiotic and endobiotic compounds. P450R is also capable of transferring electrons to cytochrome b5, heme oxygenase, the fatty acid elongation system, and other proteins. Mutations of P450R can result in disordered steroidogenesis and bone defects in Antley-Bixler syndrome and expression of P450R has been correlated with patient outcome in breast cancer. Recombinant protein corresponding to Ser62-Ser677 from human Cytochrome P450 Reductase, fused to an N-terminal Met and 6-His tag, expressed in Spodoptera frugiperda, Sf 21 (baculovirus). Predicted Molecular Weight: ~71kD Observed Molecular Weight (SDS-PAGE): ~63-69kD, reducing conditions N-terminal Sequence Analysis: Met Activity: Measured by the reduction of cytochrome C using NADPH as the cofactor. The specific activity is >1800 pmol/min/ug. Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
