INTRACELLULAR LOCALIZATION OF GLYCOGENOLYTIC AND GLYCOLYTIC ENZYMES IN WHITE AND RED RABBIT SKELETAL MUSCLE A GEL FILM METHOD FOR COUPLED ENZYME REACTIONS IN HISTOCHEMISTRY

A gel film technique has been developed for the histochemical localization of phosphorylase, phosphoglucomutase, hexokinase, glucosephosphate isomerase, phosphofructokinase, aldolase and triosephosphate isomerase. The staining reaction consists principally in coupling the specifically catalyzed reaction to a NADH 2 - or NADPH 2 -producing dehydrogenase reaction, which can be visualized by the phenazine methosulfate-mediated reduction of nitro-blue tetrazolium. The intracellular distribution of the respective enzymes was investigated in white and red rabbit skeletal muscles. Hexokinase was found to be associated with the mitochondria, and possibly also with the sarcolemma. A different type of location was observed for the other enzymes. These enzymes were found to be located at the site of the isotropic bands. Although it is suggested that these enzymes are located within the interfilamentary sarcoplasm of the actin filaments, no definite conclusion could be made on the basis of the presented histochemical findings. Especially, it could not be excluded that these enzymes might as well be associated with the transversal sarcotubular system. The very high concentration of glycogenolytic and glycolytic enzymes within the interfilamentary sarcoplasm or the transverse sarcotubular network suggests that these enzymes occur in the state of a labile multienzyme system.