An effective reactivation of alkaline phosphatase in hard tissues completely decalcified for light and electron microscopy

Summary An effective procedure for reactivating alkaline phosphatase in tissues decalcified completely for light and electron microscopy was presented. It was indicated that an Mg ion supply as reactivator in the decalcified sections before, not during, incubation for demonstration of the enzyme was important. In addition, choice of buffer solutions as Mg ion solvent and as rinsing solution for the sections after reactivation were also important. Cacodylate buffer should not have been used as an Mg solvent because the reactivation effect of the Mg ion was seriously reduced. But it should have been used for rinsing reactivated sections in order to obtain reaction products at all sites of enzyme activity throughout thick sections used for electron microscopy.