title: Effect of tryptic calmodulin fragments on guanylate cyclase activity from Paramecium tetraurelia.
abstract: Tryptic bovine brain calmodulin fragments 1-77 or 1-106 reactivated La-inactivated ciliary guanylate cyclase from Paramecium dose-dependently up to 60%. They were 20-fold less potent compared to bovine brain calmodulin. Fragment 78-148 was even less active. Concomitant addition of fragments 1-77 and 78-148 had no additive effect. Genetically engineered calmodulin lacking a blocked amino terminus and trimethyllysine at position 115 reactivated La-treated guanylate cyclase as good as bovine brain calmodulin. After detergent solubilization of La-inactivated guanylate cyclase intact bovine brain calmodulin and calmodulin fragments 1-77 and 78-148 were equipotent. 80% Reactivation was obtained with 40 microM of either fragment.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology*; D002412:Cations; D002923:Cilia / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D004793:Enzyme Reactivators; D006162:Guanylate Cyclase / Q000378:metabolism*; D007811:Lanthanum / Q000494:pharmacology; D010247:Paramecium / Q000201:enzymology*; D010446:Peptide Fragments / Q000494:pharmacology*; D013324:Strontium / Q000494:pharmacology; D014357:Trypsin
chemical_list: D002147:Calmodulin; D002412:Cations; D004793:Enzyme Reactivators; D010446:Peptide Fragments; D007811:Lanthanum; D014357:Trypsin; D006162:Guanylate Cyclase; D002118:Calcium; D013324:Strontium