title: pH-dependence of photo-induced electron transfer in zinc-substituted sperm whale myoglobin.
abstract: The electron transfer between the excited triplet state of zinc-substituted sperm whale myoglobin and Cu2+ has been studied by following the decay rate of delayed fluorescence. The Cu2+ bound on the surface of the myoglobin molecule are efficient quenchers of the excited electron state of Zn-myoglobin. Two bimolecular rate constants of quenching (KQ) for every pH investigated have been calculated. The pH-dependence of KQ1 indicates that the protonation of one amino acid residue (His-GH1 (119] is important for the process. Our results support the idea of the common nature of the mechanism of quenching by Cu2+ and oxidation of oxymyoglobin by Cu2+.
authors.affiliation: Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Sofia.
authors.forename: A C
authors.initials: AC
authors.lastname: Shosheva
authors.forename: P K
authors.initials: PK
authors.lastname: Christova
authors.forename: B P
authors.initials: BP
authors.lastname: Atanasov
mesh_terms: D000818:Animals; D003300:Copper; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D009211:Myoglobin; D010084:Oxidation-Reduction; D010777:Photochemistry; D013050:Spectrometry, Fluorescence; D014907:Whales; D015032:Zinc
chemical_list: D009211:Myoglobin; D003300:Copper; D015032:Zinc