title: A selective stepwise heme oxygenase model system: an iron(IV)-oxo porphyrin π-cation radical leads to a verdoheme-type compound via an isoporphyrin intermediate.
abstract: The selective oxidation of the α-position of two heme-Fe(III) tetraarylporphryinate complexes occurs when water(hydroxide) attacks their oxidized Cmpd I-type equivalents, high-valent Fe(IV)═O π-cation radical species ((P(+•))Fe(IV)═O). Stepwise intermediate formation occurs, as detected by UV-vis spectroscopic monitoring or mass spectrometric interrogation, being iron(III) isoporphyrins, iron(III) benzoyl-biliverdins, and the final verdoheme-like products. Heme oxygenase (HO) enzymes could proceed through heterolytic cleavage of an iron(III)-hydroperoxo intermediate to form a transient Cmpd I-type species.
authors.affiliation: Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States.
authors.forename: Isaac
authors.initials: I
authors.lastname: Garcia-Bosch
authors.forename: Savita K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Karlin
mesh_terms: D002412:Cations / Q000737:chemistry / Q000378:metabolism; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D006418:Heme / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D008665:Metalloporphyrins / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure
chemical_list: D002412:Cations; D005609:Free Radicals; D008665:Metalloporphyrins; C099547:verdoheme; C066317:ferryl iron; D006418:Heme; D007501:Iron; D006419:Heme Oxygenase (Decyclizing)