title: Myosin from striated adductor muscle of Chlamys nipponensis akazara.
abstract: Myosin was isolated from striated adductor muscle of Akazara shell-fish, and purified on DEAE-Sephadex A50. The sedimentation constant (s 20,2 0 W) and the intrinsic viscosity, [eta] of Akazara myosin thus purified were estimated to be 6.6 S and 2.10 dl/g, respectively. In many respects, Akazara myosin was similar to scallop myosin. (1) Only one size of light-chain component (17,000 daltons) was detectable in SDS-gel electrophoresis of Akazara myosin, but two types of light-chain component were seen in urea-gel electrophoresis; these were equivalent to EDTA-light chain and SH-light chain of scallop myosin. The molar ratio of heavy chain (206,000 daltons), EDTA-light chain, and SH-light chain in Akazara myosin was estimated, from the staining densities of gel-electrophoretic bands, to be approximately 1 : 1 : 1. (2) EDTA-washing procedure removed EDTA-light chain only, causing desensitization of Akazara myosin. EDTA-light chain isolated from Akazara myofibrils was able to resensitize EDTA-washed Akazara myosin. Akazara myosin, however, was found to be different from scallop myosin in two important properties: (1) complete removal of EDTA-light chains was required to achieve a complete loss of calcium sensitivity, and full resensitization was attained on recombination of EDTA-light chains with desensitized myosin prepared essentially free from EDTA-light chains. (2) EDTA-light chains isolated from Akazara myofibrils show a calcium-induced UV absorption difference spectrum.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002850:Chromatography, Gel; D004492:Edetic Acid; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D008970:Molecular Weight; D009132:Muscles / Q000032:analysis*; D009210:Myofibrils / Q000378:metabolism; D009218:Myosins / Q000302:isolation & purification*; D012758:Shellfish; D014461:Ultracentrifugation
chemical_list: D046911:Macromolecular Substances; D004492:Edetic Acid; D000251:Adenosine Triphosphatases; D009218:Myosins; D002118:Calcium