Enzymes in Muscle:  I. Histochemical Studies of Enzymes in Individual Muscle Fibers

Introduction  Recent histochemical studies of muscle^1-13 have demonstrated the relative activity of various enzymes in individual skeletal muscle fibers. These studies have been carried out on single muscles or fragments of muscles.Aiming to arrive at a better understanding of the energy metabolism of individual muscle fibers, we undertook a series of histochemical and quantitative studies of enzymes in skeletal muscles and heart. For histochemical studies, large serial sections were used containing several entire skeletal muscles and heart. The use of such sections made possible the study of the enzymatic profile of a large number of fibers in each skeletal muscle, and observations could be made on the distribution of the various types of fibers within each muscle. These sections also permitted a comparison between the enzymatic activity of the individual fibers of several skeletal muscles, as well as a comparison between the enzymatic activity of the fibers of