Energy transduction in the myocardial contractile protein system under normal conditions and in toxi-allergic myocarditis.
Energy transduction in purified myocardial myofibrils from normal rabbits and those having toxi-allergic myocarditis (TAM) was compared. In TAM a sharp decrease in the rate and value of ATP hydrolysis enthalpy released during free contraction of myofibrils takes place, and is accompanied by a rise in the amount of energy dissipated as heat. It is concluded that, at the early stages of shrinkage force generation during myofibril contraction in TAM, a breakdown of actin activation of Mg(2+)-ATPase activity for myosin occurs, the character of the bonds is changed, and the efficiency of myosin cross-bridge interaction with the protomeres of the actin thin filaments is decreased. The contractile process becomes wasteful.
Karsanov
N V
NV
Republican Centre of Medical Biophysics, Ministry of Health and Social Security, Republic of Georgia, Tbilisi.
Sukoyan
G V
GV
Tatulashvili
D R
DR
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology; D003285:Contractile Proteins / Q000502:physiology*; D004734:Energy Metabolism; D006868:Hydrolysis; D007700:Kinetics; D009200:Myocardial Contraction; D009205:Myocarditis / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D011817:Rabbits; D013816:Thermodynamics
D003285:Contractile Proteins; D000255:Adenosine Triphosphate