Protein, a New Fibrous Protein of Skeletal Muscle: Preparation

¹ From the Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, and the Marine Biological Laboratory, Woods Hole, Massachusetts

protein, a previously unreported fibrous protein with an electrophoretic mobility greater than that of myosin, is extracted from rabbit muscle by solutions of high ionic strength. This protein forms a complex with myosin, designated as -myosin. Partial purification of protein is achieved by two independent methods. In the first method alcohol fractionation is used. In the second, a solution of Salyrgan is used to dissociate the precipitated -myosin complex. In each method further purification is obtained by preparative electrophoresis. Neither method yields a product which is entirely homogeneous. Tropomyosin is present as a contaminant in alcohol-fractionated preparations, and has been isolated and crystallized. All efforts to derive protein from the previously known fibrous proteins of muscle have failed.