title: Model studies for heme oxygenase-catalyzed porphyrin meso hydroxylation.
abstract: [structure: see text]. Nonenzymatic model studies based on a porphyrin analogue (2,4-diacetyldeuteroporphyrin) that avoid the steric effect complications of the heme oxygenase active site were carried out to determine the polarity of the ferric hydroperoxide attacking species. Mass spectral and deuterium-labeling experiments indicate that the porphyrin meso positions that are at higher pi-electron densities in ferric 2,4-diacetyldeuteroporphyrin are selectively attacked. This supports an electrophilic aromatic substitution mechanism for the heme oxygenase-catalyzed porphyrin meso hydroxylation.
authors.affiliation: Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, and the Center for Drug Discovery and Chemical Biology, Northwestern University, Evanston, IL 60208-3113, USA.
authors.forename: Yaoqiu
authors.initials: Y
authors.lastname: Zhu
authors.forename: Richard B
authors.initials: RB
authors.lastname: Silverman
mesh_terms: D002384:Catalysis; D006418:Heme / Q000737:chemistry*; D006419:Heme Oxygenase (Decyclizing) / Q000737:chemistry*; D006900:Hydroxylation; D008652:Mesoporphyrins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D008652:Mesoporphyrins; D006418:Heme; D006419:Heme Oxygenase (Decyclizing)