[Activation of molecular oxygen by hemin complexes].
This paper considers main properties, structure of the active center and the mechanism of action of cytochromes P-450 of different origin. It compares the literature data on structural models of P-450. Three hemin complexes which are functional models of P-450 were synthesized. Hemin was covalently bonded via carboxyl or methine groups with amino groups of polymethyl methacrylate-based polymers or coordination bonded via iron with imidazole containing polymethyl methacrylate. The diimidazole coordination complex showed the highest specific activity. In H2O2-dependent reactions the complex displayed V M and K M similar to those of liver microsomal cytochrome P-450. In NADPH-dependent reactions the specific activity of the complex was only 1-3% that of cytochrome P-450. The above findings as well as the electronic and EPR-spectra suggest that the complex can be regarded as a functional but not as a structural model of cytochrome P-450.