Modulation of bovine serum amine oxidase activity by hydrogen peroxide

Paola Pietrangeli, Stefania Nocera, Paola Fattibene, Xingtao Wang, Bruno Mondovì, Laura Morpurgo

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Bovine serum amine oxidase (BSAO), reduced by excess amine under limited turnover conditions, was over 80 inactivated by H2O2 upon oxygen exhaustion. The UV-Vis spectrum and the reduced reactivity with carbonyl reagents showed that the cofactor topaquinone (TPQ) was stabilized in reduced form. The protein large M(r) (170 kDa) prevented the identification of modified residues by amino acid analyses. Minor changes of the Cu2+ EPR signal and the formation of a radical at g = 2.001, with intensity a few percent of that of the Cu2+ signal, unaffected by a temperature increase, suggest that Cu2+-bound histidines were not oxidized and the radical was not the Cu+-semiquinolamine in equilibrium with Cu2+-aminoquinol. It may derive from the modification of a conserved residue in proximity of the active site, possibly the tyrosine at hydrogen-bonding distance of TPQ C-4 ionized hydroxyl. The inactivation reaction appears to be a general feature of copper-containing amine oxidases. It may be part of an autoregulatory process in vivo, possibly relevant to cell adhesion and redox signaling. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)174-178
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Jan 7 2000


  • Copper-amine oxidase
  • Enzyme inactivation
  • Hydrogen peroxide
  • Radical reaction
  • Topaquinone

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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