title: [Structural-functional alterations in contractile proteins in athyreotic dystrophy of the myocardium].
abstract: In athyreotic dystrophy of the heart muscle properties both actin- and myosin-containing fibers protein components are shown to change. Changes in actin-containing filaments become apparent in a decrease in superprecipitation value of hybrid actomyosin consisting of athyreotic actin and myosin from normal myocardium. Disturbances in myosin structure result in a decrease of both, the value and rate of hybrid actomyosin superprecipitation consisting of athyreotic myosin and normal actin. The value of Mg2+-ATPase activity of hybrid actomyosins does not practically differ from that of normal actomyosin. Native athyreotic tropomyosin loses its ability to activate Mg2+-ATPase of purified actomyosin but its Ca2+ sensitivity, as well as its ability to increase the superprecipitation rate of normal actomyosin do not change. The obtained data suggest that a decrease in a tension value developed by bundles of glycerinated muscle fibers of athyreotic myocardium results from changes in the properties of both actin and myosin, while a reduction in the rate of fiber contraction is caused by disturbances of myosin properties and may be of native tropomyosin as well.
mesh_terms: D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D009202:Cardiomyopathies / Q000209:etiology / Q000503:physiopathology*; D003285:Contractile Proteins / Q000378:metabolism*; D007700:Kinetics; D009137:Muscular Dystrophy, Animal / Q000209:etiology / Q000503:physiopathology*; D009218:Myosins / Q000378:metabolism; D013965:Thyroidectomy; D014335:Tropomyosin / Q000378:metabolism
chemical_list: D000199:Actins; D003285:Contractile Proteins; D014335:Tropomyosin; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins
vernacular_title: Strukturno-funktsional'nye izmeneniia v kontraktil'nykh belkakh pri atireoznoĭ distrofii miokarda.