title: [Detection by thermal denaturation of damages to the Na pump in the myocardial sarcolemma in stress and the role of lipid peroxidation in this process].
abstract: The determination of ATP-hydrolytic activity of Na pump does not always reveal the enzyme damage in vivo. The method assessing Na, K-ATPase molecular conformational stability in the rat heart sarcolemma based on thermal denaturation is suggested. After a prolonged emotional-painful stress (EPS) the activity of Na, K-ATPase dropped by 20%, as the rate of its thermal denaturation in the range of 50-60 degrees C increased 2-3-fold. Thermodynamic calculations have demonstrated a decrease in Ea, delta H and delta S* of Na, K-ATPase thermal denaturation process after EPS. An analogous enzyme damage was found after the activation of lipid peroxidation in sarcolemma membrane suspension. These results imply that essential changes in intra- and supra-molecular properties of Na, K-ATPase under EPS may be detected by thermal denaturation. Lipid peroxidation is a most likely reason for EPS-induced Na pump damage.
mesh_terms: D000818:Animals; D004355:Drug Stability; D006358:Hot Temperature; D007473:Ion Channels / Q000201:enzymology*; D008054:Lipid Peroxides / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D010084:Oxidation-Reduction; D011489:Protein Denaturation; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013315:Stress, Psychological / Q000201:enzymology*; D013816:Thermodynamics
chemical_list: D007473:Ion Channels; D008054:Lipid Peroxides; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase
vernacular_title: Vyiavlenie s pomoshch'iu termodenaturatsii povrezhdeniĭ Na-nasosa sarkolemmy miokarda pri stresse i rol' perekisnogo okisleniia lipidov v étom protsesse.