Subcellular localization of enzymes

Localization of enzyme activity at the subcellular level requires techniques that have been essentially developed for the conventional light microscopic histochemistry and modified to fulfull the requirements of high resolution. Such procedures are manipulated in a certain sequence that starts with a short period of fixation, capture of the enzyme activity, postosmication and then dehydration followed by embedding of the specimen in a suitable plastic medium. References for the study of some selected enzymes pertinent to the hepatocytic organelles and their response under varied conditions are given as an example of the various procedures applied. Absence of glucose-6-phosphatase activity is currently used as a marker for the detection of early formation of preneoplastic cells in the liver of experimental animals treated with hepatocarcinogens and other agents.