LIGHT-MICROSCOPIC VISUALIZATION OF SEMICARBAZIDE-SENSITIVE AMINE OXIDASE (BENZYLAMINE OXIDASE) USING A CERIUM METHOD

Light microscopic histochemical studies to visualize semicarbazide-sen sitive and H2O2-generating amine oxidase (SSAOX, benzylamine oxidase, BAOX; EC 1.4.3.6?) are usually performed with the coupled peroxidatic oxidation technique of Ryder et al. [25]. For methodological reasons t his procedure has its limitations and was therefore replaced by a more reliable and easier to perform cerium-DAB-H2O2-Co technique. With thi s method SSAOX was studied in many organs of various laboratory rodent s and marmosets and in human placenta. Independent of the species the enzyme was present mostly in the plasma membrane of nearly all vascula r and non-vascular smooth muscle cells. However, there was a species-d ependence of SSOX activity; the highest amounts of stain were found in gerbils and marmosets. In addition, the enzyme was found in these two species in the capillary endothelium of some extra-nervous tissues. T he plasma membrane localization of SSAOX and plasma membrane-associate d H2O2 production suggest a functional role for the enzyme different f rom that of other amine oxidases which appear to be primarily involved in intracellular amine detoxification or degradation.