Cu-I-semiquinone radical species in plant copper-amine oxidases

The intermediate Cu-1-semiquinone radical species in the catalytic mechanis m of copper-amine oxidase from Lens esculenta and Pisum sativum seedlings h as been studied by optical, Raman resonance and ESR spectroscopies and by s topped-flow and temperature-jump measurements. Treatment of highly purified enzyme preparations with good, poor or suicide substrates, under anaerobic and aerobic conditions, at different pH values and temperatures, makes it possible to generate, detect and characterize this free radical intermediat e. (C) 1999 Federation of European Biochemical Societies.