title: Preparation and initial characterization of the compound I, II, and III states of iron methylchlorin-reconstituted horseradish peroxidase and myoglobin: models for key intermediates in iron chlorin enzymes.
abstract: To better understand the spectral properties of high valent and oxyferrous states in naturally occurring iron chlorin-containing proteins, we have prepared the oxoferryl compound I derivative of iron methylchlorin-reconstituted horseradish peroxidase (MeChl-HRP) and the compound II and oxyferrous compound III states of iron MeChl-reconstituted myoglobin. Initial spectral characterization has been carried out with UV-visible absorption and magnetic circular dichroism. In addition, the peroxidase activity of iron MeChl-HRP in pyrogallol oxidation has been found to be 40% of the rate for native HRP. Previous studies of oxoferryl chlorins have employed tetraphenylchlorins in organic solvents at low temperatures; stable oxyferrous chlorins have not been previously examined. The present study describes the compound I, II, and III states of histidine-ligated iron chlorins in a protein environment for the first time.
authors.affiliation: Department of Chemistry and Biochemistry, School of Medicine, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Coulter
authors.forename: J
authors.initials: J
authors.lastname: Cheek
authors.forename: A P
authors.initials: AP
authors.lastname: Ledbetter
authors.forename: C K
authors.initials: CK
authors.lastname: Chang
authors.forename: J H
authors.initials: JH
authors.lastname: Dawson
mesh_terms: D000818:Animals; D005290:Ferric Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D005296:Ferrous Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006736:Horses; D008665:Metalloporphyrins / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D008665:Metalloporphyrins; D009211:Myoglobin; C422651:oxoferrylchlorin; C422652:oxyferrouschlorin; D006735:Horseradish Peroxidase