부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.bbrc.2007.09.085 Byline: Ilia G. Denisov (a), John H. Dawson (b), Lowell P. Hager (a), Stephen G. Sligar (a)(c) Keywords: Chloroperoxidase; Cytochrome P450; Peroxo-ferric intermediate; Cryogenic spectroscopy; Radiolytic reduction; Heme enzyme Abstract: The hydroperoxo-ferric complex, or Compound 0 (Cpd 0), is an unstable transient intermediate common for oxygen activating heme enzymes such as the cytochromes P450, nitric oxide synthases, and heme oxygenases, as well as the peroxidases and catalases which utilize hydrogen peroxide as a source of oxygen and reducing equivalents. Detailed understanding of the mechanism of oxygen activation and formation of the higher valent catalytically active intermediates in heme enzyme catalysis requires the structural and spectroscopic characterization of this immediate precursor, Cpd 0. Using the method of cryoradiolytic reduction of the oxy-ferrous heme complex, we have prepared and characterized hydroperoxo-ferric complex in chloroperoxidase (CPO) and compared this to the same intermediate generated in cytochrome P450 CYP101. Optical absorption spectrum of Cpd 0 in CPO has a Soret band at 449nm and poorly resolved [alpha], [beta] bands at 576 and 546nm. Author Affiliation: (a) Department of Biochemistry, 116 Morrill Hall, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801, USA (b) Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29205, USA (c) Department of Chemistry, Center for Biophysics and Computational Biology, College of Medicine, University of Illinois, Urbana, IL 61801, USA Article History: Received 15 September 2007