... (inset), using the relationship [B] ⁄ [F] ¼k(Bmax– B), where [B] is the bound ligand concentration, [F] is the free ligand concentration, Bmaxis the maximum ligand amount, and k is the affinity ... evidence of the nature of the ligand responsible for the observed conformationaltransition. Thus, to discriminate between the effect dueto the rise in free Ca2+from that induced by the inter-action ... concentra-tions of the metal ion [45]. The addition of E64, a syn-thetic inhibitor of calpain, did not modify the intensityof the signal observed in the presence of Ca2+alone. The increase in the mAb-binding...