title: Calcium-dependent hydrophobic chromatography of calmodulin, S-100 protein and troponin-C.
abstract: We have demonstrated calcium-dependent hydrophobic interactions among calmodulin, S-100 protein and troponin-C and a homologous series of omega-aminoalkyl-agaroses. The three Ca2+-binding proteins were retained on the column of agarose substituted with omega- aminooctyl or even longer with alkylamine, in the presence of Ca2+ and 0.15 M NaCl. As these proteins were not retained on the column with shorter alkylamine 'arms' (N = 2, 4), they are probably successively absorbed with a higher affinity to the hydrophobic agarose column. Calmodulin and S-100 protein were eluted from the aminoocytl -agarose column with 1 mM EGTA in the presence of 0.15 M NaCl and the elution of troponin-C was Ca2+-independently carried out with 0.3 M NaCl. On the other hand, S-100 and troponin-C were eluted Ca2+-dependently from aminodecyl -agarose in the presence of 1 M NaCl and half the amount of the calmodulin applied was eluted with 1 M NaCl. As there are obvious differences among the three Ca2+-binding proteins with regard to chromatographic behavior on omega-aminoalkyl-agarose columns, our results suggest that these three proteins expose different hydrophobic regions following Ca2+-induced conformational changes and, if so, such would explain the interaction with aminoalkyl-agaroses.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002118:Calcium; D002147:Calmodulin / Q000302:isolation & purification*; D002417:Cattle; D002846:Chromatography, Affinity / Q000379:methods; D002850:Chromatography, Gel / Q000379:methods; D009132:Muscles / Q000378:metabolism; D011485:Protein Binding; D011817:Rabbits; D009418:S100 Proteins / Q000302:isolation & purification*; D014336:Troponin / Q000302:isolation & purification*; D019209:Troponin C
chemical_list: D002147:Calmodulin; D009418:S100 Proteins; D014336:Troponin; D019209:Troponin C; D002118:Calcium