Formation of hybrid complexes between Ca and the ionophores bromolasalocid (Br-X537A) and A23187.

The ionophores A23187 and bromolasalocid (Br-X537A) acted synergistically in translocating Ca(2+) from an aqueous into an organic immiscible phase or in mediating Ca(2+) transport across the organic phase, the effects obtained in the simultaneous presence of both ionophores being greater than those expected from a summation of the individual effects of each ionophore. The nuclear magnetic resonance spectrum obtained when the complexation of Ca(2+) occurred in the presence of both ionophores differed strikingly from the individual spectra obtained with the A23187-Ca and Br-X537A-Ca complexes. These findings indicate that the two ionophores are able to form hybrid complexes with Ca(2+).