title: Effect of calcium on the structure-function relationship of (Na+ + K+)-ATPase in cardiac sarcolemma.
abstract: Calcium-induced changes in (Na+ + K+)-ATPase activity and structural changes of membrane bound proteins in rat heart sarcolemma were investigated. Increasing concentrations of Ca2+ (0.1-8.0 mmol.l-1) gradually inhibited the (Na+ + K+)-ATPase activity and decreased the alpha-helix content of sarcolemmal proteins. Mathematical and graphical analysis of observed data yielded a quantitative relationship between Ca2+-induced changes in (Na+ + K+)-ATPase activity and the secondary structure of membrane proteins in cardiac sarcolemma.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D008433:Mathematics; D009206:Myocardium / Q000166:cytology*; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000502:physiology*; D013329:Structure-Activity Relationship
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium