Aminoglycosides as substrates and inhibitors of peroxidases: a possible role of these antibiotics against myeloperoxidase-dependent cytotoxicity

Alessandro Arcovito, A Lorrai, A Padiglia, Rosaria Medda, A Bellelli, G. Floris

Risultato della ricerca: Contributo in rivistaArticolo in rivistapeer review

Abstract

The kinetics of the catalytic cycle of myeloperoxidase and of horseradish peroxidase reacting with aminoglycosides have been studied by conventional and stopped-flow spectrophotometry. Aminoglycosides acted as one-electron reducing substrates converting compound I, formed when stoichiometric amounts of hydrogen peroxide were added to the enzyme, to compound II, and compound II to the resting, ferric enzyme. The latter gradually decayed into a further spectroscopic derivative (lambda(max) = 540 and 403 nm) tentatively identified as a complex of ferric heme with the antibiotic oxidation product(s), and the resulting enzyme was fully inactivated. Since myeloperoxidase is the only human enzyme known to convert chloride ions into the cytotoxic hypochlorous acid, the data presented in this paper bear relevance to the pharmacological effects of aminoglycoside antibiotics, which, while inhibiting bacterial growth, also prevent oxidative cellular damage caused by hypochlorous acid aging as substrates and inhibitors of myeloperoxidase.
Lingua originaleEnglish
pagine (da-a)97-104
Numero di pagine8
RivistaJournal of Protein Chemistry
Volume21
Stato di pubblicazionePubblicato - 2002

Keywords

  • Anti-Bacterial Agents
  • Cell Survival
  • Enzyme Inhibitors
  • Horseradish Peroxidase
  • Kanamycin
  • Kinetics
  • Peroxidase
  • Peroxidases
  • Spectrophotometry

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