title: Hydrophobic properties of Tetrahymena calmodulin related to the phosphodiesterase activity.
abstract: We have examined hydrophobic properties of Tetrahymena CaM using the uncharged probe, n-phenyl-1-naphthylamine (NPN) fluorescence. The maximal fluorescence intensity of Tetrahymena calmodulin (CaM) is less than 1/12 of that of the bovine brain CaM. In the phosphodiesterase activation, the potency of Tetrahymena CaM, which was represented by reciprocals of the quantity of CaM required for half-maximal activation of enzyme was 22.7% respectively, of that of the bovine brain CaM. Here, Tetrahymena CaM had less hydrophobic groups exposed in the presence of Ca2+. Then Ca2+-CaM dependent enzymes require much amount of Tetrahymena CaM, comparing with the bovine brain CaM.
mesh_terms: D015057:1-Naphthylamine / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D001923:Brain Chemistry; D002118:Calcium / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002147:Calmodulin / Q000378:metabolism / Q000494:pharmacology*; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013768:Tetrahymena / Q000032:analysis*
chemical_list: D002135:Calcium-Binding Proteins; D002147:Calmodulin; C005444:N-phenyl-1-naphthylamine; D015057:1-Naphthylamine; D010727:Phosphoric Diester Hydrolases; D002118:Calcium