PROBES OF CYTOCHROME P450 STRUCTURE

Publisher Summary This chapter discusses probes of cytochrome P-450 structure. The cytochrome P-450 monoxygenases assume a leading role in the elucidation of oxygenation and O 2 reduction mechanisms. In measurements with pure components, they supplement Mb and Hb data in the identification of states and structures associated with heme dioxygen binding and activation processes. The proposed reaction cycle of heme states in hepatic microsomes can be taken as appropriate for all P-450 cytochromes, although two basic modes of electron transport have been identified with P-450 monoxygenase systems viz. the microsomal and the mitochondrial-microbial. The emerging properties characterizing the unique features of the ρ450 heme structure, thus, converge in a unified effort to elucidate the molecular mechanism of action. This chapter discusses the essential X-ray diffraction parameters for the three crystalline forms of P-450 CAM determined in the laboratory of Kraut and Poulos. It illustrates single-crystal polarized absorption spectra of P-450 CAM .