Characterization, assay, and substrate specificity of plant polyamine oxidases

Polyamine oxidation is the main catabolic process of polyamines. This process is crucial because not only it participates in the regulation of the endogenous titers of polyamines but also it generates hydrogen peroxide, which can act as a signaling molecule. The recent identification of polyamine oxidases that differ in substrate specificity and mode of action in plants necessitates the use of additional techniques for their characterization based on the determination of the end-product. Herein, we describe the most widely used techniques as well as new techniques that can be used for analysis of the newly identified polyamine oxidases.