title: Identification of the calmodulin-binding components in canine cardiac sarcolemma.
abstract: The covalent attachment of 125I-calmodulin to canine cardiac sarcolemma has been achieved using the crosslinker dithiobis(succinimidyl propionate). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crosslinked products revealed three 125I-calmodulin-labeled components of Mr = 125,000, 108,000 and 81,000. That the formation of these three components was Ca-dependent and inhibited by unlabeled calmodulin, or calmodulin antagonists, would indicate that the formation of these components was calmodulin-specific. The size of these 125I-labeled components was unchanged over a range of crosslinker or 125I-calmodulin concentrations indicating that they represent 1:1 complexes between 125I-calmodulin (Mr = 17,000) and Mr = 108,000, 91,000 and 64,000 sarcolemma components respectively. The labeling of these components with 125I-calmodulin was not enhanced when endogenous calmodulin was removed from sarcolemma. The possible identity of the 125I-calmodulin-labeled sarcolemma components is discussed.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004285:Dogs; D004533:Egtazic Acid / Q000494:pharmacology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D009206:Myocardium / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*
chemical_list: D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D004533:Egtazic Acid; D008274:Magnesium; D002118:Calcium