title: On the mechanism of interaction between calmodulin and calmodulin-dependent proteins.
abstract: Molecular and kinetic studies of the interaction between calmodulin and calmodulin-dependent proteins have been reviewed. Several calmodulin-dependent proteins have been purified to homogeneity and characterized in terms of subunit structure in recent years. The results indicate that these proteins do not contain a common subunit as the basis of calmodulin binding. A monoclonal antibody capable of interacting with several calmodulin-dependent proteins has been obtained, suggesting that these proteins contain common structure. It seems that hybridoma technology may be used for probing calmodulin-binding domains in the calmodulin-dependent proteins. Using a fluorescent-labelled cyclic nucleotide phosphodiesterase, the interaction between calmodulin and the enzyme in the absence of Ca2+ can be demonstrated, and the equilibrium constant of the reaction can be determined. The study further defines the multiple interactions in the activation of the cyclic nucleotide phosphodiesterase by Ca2+ and calmodulin. Previous kinetic results along with the present results are summarized and used to elucidate the regulatory significance of the multiple Ca2+-binding of calmodulin.
mesh_terms: D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000502:physiology*; D002148:Calmodulin-Binding Proteins; D004789:Enzyme Activation; D005453:Fluorescence; D006801:Humans; D007700:Kinetics; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D011506:Proteins / Q000032:analysis / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D011506:Proteins; D010749:Phosphoprotein Phosphatases; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D002118:Calcium