Copper amine oxidases (CuAOs) involved in polyamine catabolism are emerging as physiologically relevant enzymes for their involvement in plant growth, differentiation and defence responses to biotic and abiotic stress. In this chapter, we describe two spectrophotometric and one polarographic method for determining CuAO activity in plant tissues. Some aspects related to cell wall association of apoplastic CuAOs and possible interference of plant metabolites with the enzymatic activity assays are also considered.
Keywords: Copper-containing amine oxidase; Flavin-containing polyamine oxidase; Peroxidase-coupled assay; Polyamines.