Raman characterization of human leukocyte myeloperoxidase and bovine spleen green haemoprotein. Insight into chromophore structure and evidence that the chromophores of myeloperoxidase are equivalent

摘要: Soret excitation resonance Raman spectroscopy has been used to characterize dimeric human leukocyte myeloperoxidase (donor:hydrogen peroxide oxidoreductase, EC 1.11.1.7) and monomeric bovine spleen green haemoprotein. The spectra of the two proteins, under same conditions iron valence ligation, are essentially identical. Owing strong symmetry reduction effects, more complex than usually observed for haemoproteins. It is possible, however, assign high-frequency vibrations and, from these assignments, determine structural features chromophores. In resting protein, adopts a six-coordinate high-spin configuration in both proteins; cyanide addition produces low-spin species, ferrous enzymes appears be five-coordinate high-spin. proteins stable laser do not photoreduce illumination. No evidence found unusual peripheral substituents, such as formyl or protonated Schiff's base group, conjugation with main chromophore native protein. vibrational data consistent an chlorin chromophore, although other electronic those produced by porphyrin ring reduction, necessary account optical properties proteins. similarity haemoprotein indicates that sites equivalent.