title: Radicals involved in photoallergen/protein interactions.
abstract: Aqueous solutions (pH = 8) of both 3,3'-dimethyl and 4,4'-dimethyl substituted analogues of the photoallergen fentichlor (bis(2-hydroxy-5-chlorophenyl)sulphide) produced stable semiquinone radicals when irradiated with u.v. light (greater than 310 nm). These radicals have been characterised using electron spin resonance techniques: the results confirm the assignment of hyperfine coupling constants for the parent fentichlor radical. The binding of fentichlor to HSA was found to be partly oxygen dependent demonstrating a role for semiquinone type radicals in the binding mechanism. The stoichiometry and specificity of the binding of the dimethyl analogues to soluble proteins were found to be similar to that of fentichlor itself.
authors.affiliation: Department of Chemistry, University College, Cardiff, U.K.
authors.forename: J N
authors.initials: JN
authors.lastname: Delahanty
authors.forename: J C
authors.initials: JC
authors.lastname: Evans
authors.forename: C C
authors.initials: CC
authors.lastname: Rowlands
authors.forename: M D
authors.initials: MD
authors.lastname: Barratt
authors.forename: R U
authors.initials: RU
authors.lastname: Pendlington
mesh_terms: D000891:Anti-Infective Agents, Local / Q000009:adverse effects / Q000528:radiation effects*; D001665:Binding Sites; D002733:Chlorophenols / Q000009:adverse effects / Q000378:metabolism / Q000528:radiation effects*; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006801:Humans; D008745:Methylation; D015394:Molecular Structure; D010100:Oxygen / Q000494:pharmacology; D010777:Photochemistry; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D011506:Proteins / Q000378:metabolism*; D012709:Serum Albumin / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000891:Anti-Infective Agents, Local; D002733:Chlorophenols; D005609:Free Radicals; D011506:Proteins; D012709:Serum Albumin; C007713:fentichlor; D010100:Oxygen