LANGMUIR-BLODGETT-FILMS OF CYTOCHROME P450SCC AND ITS COMPLEX WITH ADRENODOXIN

Langmuir-Blodgett films prepared from cytochrome P450scc and its compl ex with adrenodoxin have been prepared and studied. Adrenodoxin was pr eliminarily selectively modified with fluorescein isothiocyanate and t he effect of this modification on the interaction with cytochrome P450 scc was studied. Using selectively modified adrenodoxin the ratio of t he proteins in the film was found to be 1 mole of adrenodoxin per 2 mo les of cytochrome P450scc, Langmuir-Blodgett films were also prepared from adrenodoxin-reductase and it was shown that this flavoprotein is transferred to the substrate as an apo-protein. It is also shown that the adrenodoxin-binding region of cytochrome P450scc is exposed to the subphase under all pressures in the interval studied. The relationshi p between the orientation of cytochrome P450scc-adrenodoxin complex in monolayers on the water-air interface and the pressure produced at th e interface at the moment of monolayer formation was found. Our data a re in excellent accordance with ideas on the molecular organization of cytochrome P450scc in the inner adrenocortical membrane and allows th e use of this approach to model membrane structures containing cytochr ome P450.