Cytochemical localization of malate synthase in amphibian fat body adipocytes: possible glyoxylate cycle in a vertebrate.

The adipocytes of amphibian abdominal fat bodies contain typical microperoxisomes, as indicated by their fine structure. Electron microscopic cytochemistry showed that these organelles contain the enzymes catalase, typical for peroxisomes, and malate synthase. The latter is an enzymatic component characteristic of the glyoxylate cycle, a biochemical pathway known to exist in plant glyoxysomes (peroxisomes). This metabolic pathway makes possible the net conversion of lipid to carbohydrate. Toad adipocytes may represent yet another example of vertebrate peroxisomes which contain one of the marker enzymes (malate synthase) characteristic of the glyoxylate shunt.