COMPARATIVE-STUDIES OF THE STRUCTURAL STATE OF SKELETAL-MUSCLE AND SMOOTH-MUSCLE FIBER TROPOMYOSINS IN GHOST FIBERS OF SKELETAL-MUSCLES USING FLUORESCENT-PROBES

The structural state of skeletal muscle and smooth muscle fiber tropom yosins in ghost fibers of skeletal muscles has been studied by polariz ation microfluorimetry. Tropomyosins and F-actin of ghost fibers were labeled with (iodoacetyl)-N-(5-sulfo-1-naphthyl)ethylenediamine (1,5-I AEDANS) and phalloidin-rhodamine complex, respectively. Skeletal tropo myosin bound to ghost muscle fibers was found to be more flexible than smooth muscle tropomyosin. The flexibility of thin filaments of the g host fibers labeled at F-actin by the phalloidin-rhodamine complex and containing smooth muscle tropomyosin is higher than that of thin fila ments containing the bound skeletal muscle tropomyosin.