Comparison of Tropomyosins from Cardiac and Skeletal Muscle

Abstract

No differences were found between the sedimentation coefficients, intrinsic viscosities, amino acid contents, and peptide patterns resulting from tryptic digestion of rabbit cardiac and skeletal tropomyosins. From sedimentation and viscosity data, the molecular weights of cardiac and skeletal tropomyosins were estimated to be 54,800 for both. This value is similar to previous estimates of the molecular weight of rabbit skeletal tropomyosin. No evidence was obtained for the existence in heart muscle of tropomyosin A. Of the three more abundant contractile proteins of the heart, myosin, actin, and tropomyosin, only myosin appears to differ from its skeletal counterpart.