CYTOCHEMICAL DETECTION OF PEROXISOMAL OXIDASES

The ferricyanide reduction method and the cerous chloride procedure for H2O2 detection appear to be the most reliable of the currently available techniques for the ultrastructural demonstration of peroxisomal oxidase activity. With proper fixation, suitable substrates and appropriate controls, these procedures should allow detection of the three principle oxidases of animal cell peroxisomes. At the present time, the inferior ultrastructural morphology obtained in many immunocytochemical procedures is a distinct disadvantage in utilizing this approach to oxidase localization. With improvements in technical procedures and tissue preparation, however, the inherent advantages of immunocytochemical procedures, i.e., specificity, applicability to a variety of peroxisomal components, and the ability to detect immunoreactive molecules such as precursors or degradation products rather than just enzymatically active forms, should allow for significant progress in the understanding of peroxisomal biogenesis and function.