Enhanced ultrastructural localization of acid phosphatase using microwave irradiation during enzyme incubation

Microwave irradiation in enzyme cytochemistry is not only advantageous for shortening procedures, but will also improve the sensitivity of histochemical detection since short periods and less fixative are required to obtain good preservation. Moreover, shorter incubation procedures will reduce the diffusion and loss of enzyme activity. Here we compared conventional incubations in a shaking waterbath at 37°C, with incubations carried out in a microwave oven. Lysosomal and extralysosomal acid phosphatase were identified using microwave irradiation. Microwave irradiation elicited enhanced reactivity of the chemicals present in the tissue, leading to the detection of minuscule concentrations of enzyme activity, which was most pronounced in the detection of extralysosomal enzyme activity. A major advantage of the microwave is the accelerated formation of reaction product. Furthermore, enzymatic preincubation or chemical treatment of the tissues is no longer necessary. By shortening the incubation time, the danger of artificial precipitations and diffusion of the final reaction product are reduced. The sensitivity and reproducibility of the enzymatic reaction are increased. Consequently, microwave irradiation during enzyme incubation leads to a highly specific localization of acid phosphatase.