ISOLATION AND CHARACTERIZATION OF TWO β-TYPE CARDIAC MYOSIN IN THE CANINE ATRIUM

• Published in: JAPANESE CIRCULATION JOURNAL Vol. 52; no. 10; pp. 1191 - 1200
• Main Authors: KOMURO, ISSEI, TAKAKU, FUMIMARO, NOMOTO, KAZUOMI, YAZAKI, YOSHIO
• Format: Journal Article
• Language: English
• Published: Kyoto The Japanese Circulation Society 1988; Japanese Circulation Society
• Subjects: Adenosine Triphosphatases - metabolism; Analytical, structural and metabolic biochemistry; Animals; Antibodies, Monoclonal; Antigen-Antibody Reactions; Biological and medical sciences; Cardiac myosin heavy chain isozyme; Chromatography, Affinity; Contractile proteins; Dogs; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Heart Atria - analysis; Heart Atria - enzymology; Holoproteins; Hydrolysis; Isoenzymes - immunology; Isoenzymes - isolation & purification; Isoenzymes - metabolism; Monoclonal antibody; Myocardium - analysis; Myocardium - enzymology; Myosin ATPase; Myosins - immunology; Myosins - isolation & purification; Myosins - metabolism; Peptide Hydrolases; Peptide map; Proteins; Heart; Immunohistochemistry; Atrium; Vertebrata; Mammalia; Molecular structure; Beta-Peptide chain; Myosin; Contractile protein; Ox; Artiodactyla; Ungulata
• ISSN: 0047-1828; 1347-4839
• DOI: 10.1253/jcj.52.1191

Recently, we demonstrated that more β-type myosin heavy chain (HC) was expressed in the overloaded atrium, and that there were 2 structurally different β-type myosin heavy chains in the bovine heart. To determine the existence of the 2 β-type HC in other animals and to clarify the characteristics of these β-type HCs, we produced tricuspid regurgitation and pulmonary stenosis in the canine heart, and performed an immunological study using 3 monoclonal antibodies, 2 β-type specific antibodies (HMC14 and 50) and 1 α-type specific antibody (CMA19). In an immunohistochemical study, serial cryostat sections revealed that some myofibers reacted with HMC50 (HCβ2), but almost no fibers were labeled with HMC14 in the normal atrium. However, in overloaded atria, not only HCβ2 but the HC, reacted with HMC14 (HCβ1). By affinity chromatography, HCβ2 was fractionated from normal atrial myosin using HMC50 and HCβ1 was fractionated from overloaded atrial myosin using HMC14. These 2 HCβ's were subjected to digestion by -chymotrypsin, staphylococcus aureus V8 protease, and cyanogen bromide, and proved to have different peptide fragments. In respect to enzymatic properties, the Ca2+-activated ATPase activities of HC1 and 2 were almost the same but lower than that of HC. We concluded that the isozymic transition of HC to HC in the atrium was experimentally induced by hemodynamic overload and that HC1, which was hardly recognized in the normal atrium but highly induced by overload, was structurally different from HC2, as expressed in the normal atrium.