5-S-Cysteinyldopa, a diffusible product of melanocyte activity, is an efficient inhibitor of hydroxylation/oxidation reactions induced by the Fenton system
| Autor: | Alessandra Napolitano, Sofia Memoli, Giuseppe Prota, Anthony J. Nappi, Marco d'Ischia |
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| Přispěvatelé: | Napolitano, A., Memoli, S., Nappi, A. J., D'Ischia, M., Prota, G., Napolitano, Alessandra, S., Memoli, A. J., Nappi, D'Ischia, Marco, G., Prota |
| Rok vydání: | 1996 |
| Předmět: |
Radical
Biophysics Borohydrides Hydroxylation Iron Chelating Agents Biochemistry Medicinal chemistry Redox chemistry.chemical_compound medicine Organic chemistry Chelation Anaerobiosis Hydrogen peroxide Molecular Biology Edetic Acid Chelating Agents Free Radical Scavengers Hydrogen Peroxide Aerobiosis Salicylates Dihydroxyphenylalanine Cysteinyldopa chemistry Deoxyribose Melanocytes Ferric Salicylic Acid Oxidation-Reduction Salicylic acid medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - General Subjects. 1291:75-82 |
| ISSN: | 0304-4165 |
| Popis: | Interest in 5-S-cysteinyldopa (5-S-CD), a major excretion product of normal and malignant melanocytes, has traditionally concentrated on its significance as a biosynthetic precursor of pheomelanins, the characteristic pigments of red hair, and as a specific biochemical marker for monitoring melanoma progression. The present study shows that 5-S-CD is a potent inhibitor of hydroxylation/oxidation reactions mediated by hydrogen peroxide and the Fe2+/EDTA complex under both aerobic and anaerobic conditions. The inhibitory effect of 5-S-CD, as determined by the deoxyribose and salicylic acid assays in phosphate buffer (pH 7.3), is much stronger than that of dopa, acetylsalicylic acid and mannitol, increases with increasing ligand-to-metal ratio, and is inversely proportional to the concentration of EDTA present in the Fenton system. Spectrophotometric evidence and competition experiments indicate that 5-S-CD forms a chelate complex with ferric ions (lambda(max) = 500 nm at pH 7.3), which may account for both an altered production of hydroxyl radicals by the Fenton reagent and a site-specific localization of oxidative damage on the chelate complex itself. |
| Databáze: | OpenAIRE |
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