Complexation studies on inositol-phosphates, VI. Al 3+ complexes of DL- myo-inositol 1,4,5-triphosphate and D- myo-inositol 1,2,6-triphosphate

Abstract

Aluminum complexes of D- myo-inositol 1,2,6-triphosphate (Ins(1,2,6)P 3) and DL- myo-inositol 1,4,5-triphosphate (Ins(1,4,5)P 3) have been studied by potentiometry at 25°C in a 0.1 M tetrabutylammonium bromide medium. Both ligands form AlHL, AlL, and AlOHL species whereas Ins(1,2,6)P 3 forms, in addition, an Al 2L complex and Ins(1,4,5)P 3 an Al(OH) 2L species. In an attempt to assess the biological significance of the Al 3+ binding to Ins(1,4,5)P 3, the results were compared to the Al 3+-ATP complexes that have been found in similar medium conditions. Taking into account the relative stability of the complexes of both systems, it appears likely that the intracellular second messenger system involving Ins(1,4,5)P 3 may be disturbed by the presence of the aluminum cation.