The Peroxisome

Abstract

For many years after its biochemical characterisation by de Duve in the 1960s (section 1.2.2), the peroxisome was little more than a curiosity. Its sedimentation in the ultracentrifuge could be followed by the presence of the marker enzyme, catalase. Under the appropriate conditions of differential centrifugation and density-gradient centrifugation, the peroxisomes of rat liver could be separated from lysosomes, mitochondria, and microsomes. Biochemical analysis revealed a content of several oxidative enzymes; the feature common to all these enzymes was that they generated hydrogen peroxide (H₂O₂) as a product of their reaction (figure 7.1). Thus, it was considered that the peroxisome had developed in the course of evolution in order to protect the cell from the potentially harmful effects of these particular oxidative enzymes.