Myosin chains of myocardial tissue - purification and immunological properties

Since the myosin purification procedures available did not give a pure preparation of heavy and light myosin chains of dog myocardial tissue, a new purification procedure has been developed which gives pure chains and allows for immunological comparative studies. The procedure is based on differential salt precipitation of the various chains and a buffer system which reduces protein interaction. The heavy (MW 2.1 x 10⁵) and the two light chains (MW 2 x 10⁴ and 3 x 10⁴) give single bands on SDS polyacrylamide gels. An antiserum to each of the chains has been developed giving single precipitin lines and showing no cross-reaction with the other myosin components in an Ouchterlony assay. The dissociated antigen antibody complex when electrophoresed on SDS polyacrylamide gels also demonstrates the specificity of the antibody for its respective chain. The antiserum is being used as a means of myosin purification and allows for a study of the turnover rates of heavy and light chains. According to preliminary studies, the heavy chains have a shorter half-life, by several days, as compared to the light chains. In further studies a radioimmunoassay has been developed giving a sensitive quantification of myosin in small samples of tissue. This, combined with previously developed immunoassays for DNA and ribosomes allows for future studies of protein and nucleic acid turnover in hypertrophied muscle.