Inactivation of copper-containing amine oxidases by turnover products

Eur J Biochem. 2004 Jan;271(1):146-52. doi: 10.1046/j.1432-1033.2003.03913.x.


For bovine serum amine oxidase, two different mechanisms of substrate-induced inactivation have been proposed. One consists of a slow oxidation by H2O2 of a conserved residue in the reduced enzyme after the fast turnover phase [Pietrangeli, P., Nocera, S., Fattibene, P., Wang, X.T., Mondovì, B. & Morpurgo, L. (2000) Biochem. Biophys. Res. Commun.267, 174-178] and the other of the oxidation by H2O2 of the dihydrobenzoxazole in equilibrium with the product Schiff base, during the catalytic cycle [Lee, Y., Shepard, E., Smith, J., Dooley, D.M. & Sayre, L.M. (2001) Biochemistry40, 822-829]. To discriminate between the two mechanisms, the inactivation was studied using Lathyrus cicera (red vetchling) amine oxidase. This, in contrast to bovine serum amine oxidase, formed the Cu+-semiquinolamine radical with a characteristic UV-vis spectrum when oxygen was exhausted by an excess of any tested amine in a closed cuvette. The inactivation, lasting about 90 min, was simultaneous with the radical decay and with the formation of a broad band (shoulder) at 350 nm. No inactivation occurred when a thousand-fold excess of amine was rapidly oxidized in an L. cicera amine oxidase solution stirred in open air. Thus, the inactivation is a slow reaction of the reduced enzyme with H2O2, following the turnover phase. Catalase protected L. cicera amine oxidase from inactivation. This effect was substrate-dependent, varying from full protection (benzylamine) to no protection (putrescine). In the absence of H2O2, a specific inactivating reaction, without formation of the 350 nm band, was induced by some aldehydes, notably putrescine. Some mechanisms of inactivation are proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amine Oxidase (Copper-Containing) / antagonists & inhibitors*
  • Animals
  • Cattle
  • Copper / metabolism
  • Enzyme Inhibitors / isolation & purification
  • Enzyme Inhibitors / pharmacology
  • Kinetics
  • Lathyrus / enzymology*
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology*
  • Plant Proteins / antagonists & inhibitors
  • Polyamines / pharmacology
  • Spectrophotometry
  • Spermidine / pharmacology
  • Substrate Specificity


  • Enzyme Inhibitors
  • Plant Extracts
  • Plant Proteins
  • Polyamines
  • Copper
  • Amine Oxidase (Copper-Containing)
  • Spermidine