title: Inhibitory effect of bovine brain calmodulin on calmodulin-dependent stimulation of plasma membrane-bound guanylate cyclase in Tetrahymena pyriformis.
abstract: Bovine brain calmodulin (B-CaM) was shown to inhibit the native Tetrahymena calmodulin (T-CaM)-dependent activation of guanylate cyclase in Tetrahymena at the concentrations that failed to affect the basal enzyme activity. The enzyme inhibition was completely reversed by high concentration of T-CaM, but not by Ca2+. The antagonistic interaction between T-CaM and B-CaM was not observed in the calmodulin-dependent cyclic nucleotide phosphodiesterase from bovine brain. Two calmodulins migrated independently on 15% polyacrylamide gel system. These results suggest that B-CaM exerts its inhibitory effect on the guanylate cyclase activation by interacting with the calmodulin-binding site of this enzyme.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology; D002147:Calmodulin / Q000494:pharmacology* / Q000502:physiology; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors*; D007700:Kinetics; D013769:Tetrahymena pyriformis / Q000201:enzymology*
chemical_list: D002147:Calmodulin; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D006162:Guanylate Cyclase