Metal ion-induced activation of molecular oxygen in pigmented polymers

• Published in: Biochimica et biophysica acta Vol. 883; no. 1; pp. 41 - 45
• Main Authors: Hintz, P., Kalyanaraman, B.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 06.08.1986; Elsevier; North-Holland
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cations; Cattle; Copper - pharmacology; Edetic Acid - pharmacology; Electron Spin Resonance Spectroscopy; ESR; Fundamental and applied biological sciences. Psychology; H 2O 2 production; Heterocyclic compounds, pigments; Hydrogen Peroxide - metabolism; Hydroxides - metabolism; Hydroxyl Radical; Iron - pharmacology; Kinetics; Lanthanum - pharmacology; Magnesium - pharmacology; Manganese - pharmacology; Melanin autoxidation; Melanins - metabolism; Metals - pharmacology; Miscellaneous; Nickel - pharmacology; Other biological molecules; Oxidation-Reduction; Oxygen - metabolism; Redox-active metal ion; Zinc - pharmacology; Redox-active metal ion; DMPO; dopa; ESR; Melanin autoxidation; H 2O 2 production; Autoxidation; Reaction mechanism; Metal Ions; Pigments; Iron «III» Ions; Polymer; Copper II Ions; Melanin
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(86)90132-7

Diamagnetic and paramagnetic metal ions enhanced the rate of production of hydrogen peroxide during autoxidation of melanin pigments, as measured using an oxidase electrode. However, redox-active metal ions, such as Fe 3+ and Cu 2+, caused a marked decrease in H 2O 2 production. Evidence for redox-active metal ion-dependent formation of hydroxyl radicals during autoxidations of melanin pigments has been obtained using the electron spin resonance-spin trapping method. Evidence of direct reduction of Fe 3+ by melanin polymers also has been obtained using optical spectroscopy. Mechanisms of molecular activation of oxygen induced by metalionsp on melanin polymers are discussed.