title: Mössbauer, EPR and NMR studies of the acid-induced reduction and changes in spin state of ferric bleomycin.
abstract: Iron-57 Mössbauer, electron paramagnetic resonance (EPR) and H-1 nuclear magnetic resonance (NMR) studies of iron-bleomycin complexes in the pH range from 1.0 to 6.0 are reported. Sequential protonation of the ligands produces a variety of high-spin and low-spin complexes of the metal. Of particular interest is the reversible equilibrium between Fe(III)- and oxygen-stable Fe(II)-bleomycin. Below pH 3.5 Fe(II) complexes form, with maximal reduction occurring at approximately pH 2. At still lower pH, Fe(III) complexes unassociated with bleomycin become dominant. The observed reduction in the absence of exogenous reducing agents suggests the possible involvement of intramolecular autoreduction in bleomycin-mediated DNA degradation.
authors: Laboratory of Cellular and Molecular Biology, NIA/NIH, Baltimore, MD 21224.
authors: A
authors: A
authors: Levy
authors: P T
authors: PT
authors: Manoharan
authors: J M
authors: JM
authors: Rifkind
authors: J C
authors: JC
authors: Walker
authors: F C
authors: FC
authors: Haberle
authors: N G
authors: NG
authors: Kumar
authors: J D
authors: JD
authors: Glickson
authors: G A
authors: GA
authors: Elgavish
mesh_terms: D001761:Bleomycin / Q000031:analogs & derivatives; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D010084:Oxidation-Reduction; D011522:Protons; D015204:Spectroscopy, Mossbauer
chemical_list: D011522:Protons; C023503:iron bleomycin; D001761:Bleomycin