Baculovirus Expression of Bovine Cytochrome P450C17 in Sf9 Cells and Comparison with Expression in Yeast, Mammalian-Cells, and E. coli

Expression of bovine 17 α-hydroxylase cytochrome P450 (P450c17) in insect Sf9 cells using baculovirus is the fourth heterologous expression system developed for studying this enzyme. The enzyme in Sf9 cell membranes has all the expected activities and closely resembles that from the other systems: COS1 cells, yeast, and Escherichia, coli. One curious feature of baculovirus expression of this hemoprotein is that the immunodetectable P450c17 is present in an insoluble pellet when produced in the absence of added hemin and in a 10,000g supernatant when expressed in the presence of added hemin. When comparing the level of expression of bovine P450c17 in these different expression systems, E. coli produces the largest quantity per liter culture, while baculovirus produces the most molecules of P450c17 per cell.