Determination of malate synthase activity in polyacrylamide gels

It is shown that the generation of the insoluble precipitate, copper ferrocyanide, provides a distinct, rapid, and sensitive method for localizing malate synthase in polyacrylamide gels. Both enzymes of the glyoxylate cycle, isocitrate lyase and malate synthase, can now be specifically stained using the same polyacrylamide gel system. This can contribute substantially to elucidating the developmental or adaptive patterns of the glyoxylate cycle and in determining the degree of homology of glyoxylate cycle enzymes from different organisms or organelles. These techniques also provide a simple method for establishing the occurrence of isoenzymes. Finally, the ability to detect a reaction capable of reducing ferricyanide to form cooper ferrocyanide suggests that this technique may be useful for localization of many of the enzymes which generate CoASH (18,19).