Expression of a recombinant derivative of human aromatase P450 in insect cells utilizing the baculovirus vector system

Aromatase P450 (P450arom) is the enzyme responsible for estrogen biosynthesis. Studies of the relationship of the function of this enzyme to its structure have been hampered by lack of a suitable preparation. In the present report we describe the expression of a recombinant derivative of P450arom in insect cells by means of the baculovirus vector system. This protein, which lacks the first 41 amino acids from the N-terminus, and hence the membrane-spanning region, has spectral properties and activity similar to that of the wildtype protein. Moreover, the presence of a hexameric histidine tag at the C-terminus permits its facile purification by means of nickel-agarose affinity chromatography. This system permits the synthesis of quantities of a biologically active derivative of P450arom suitable for studies designed to explore the relationship of function to structure.