title: Aequorin luminescence: relation of light emission to calcium concentration--a calcium-independent component.
abstract: Light emission from the calcium-sensitive bioluminescent protein aequorin was measured at calcium ion concentrations of 10(-9) to 10(-2) molar. At very low Ca2+ concentations, light emission is independent of calcium ion concentration. The maximum slope of the log-log plot of light as a function of calcium ion concentration is about 2.5. The complete relation is well described by a two-state model involving three calcium-binding sites.
mesh_terms: D000331:Aequorin / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D007700:Kinetics; D049449:Luminescence; D008954:Models, Biological; D011506:Proteins / Q000378:metabolism
chemical_list: D011506:Proteins; D000331:Aequorin; D002118:Calcium