Capability of arsonolipids to transport divalent cations: a Pressman cell study

The ability of the newly synthesized arsonolipids (2,3-diacyloxypropylarson ic acids) to transport cations was studied using the Pressman cell. Experim ental results demonstrate that arsonolipids are much more efficient carrier s of Ca2+ and Mg2+ than natural phosphatidic acid in the Pressman cell expe riments. The ability of arsonolipids to transfer Ca2+ is affected by the li pid side chain length in the order: C-12 much greater than C-14 congruent t o C-16. Ca2+ is transferred faster than Mg2+, suggesting that the latter is more tightly bound to the arsonolipids. The transfer kinetic curves are pa rabolic for C-12, while initially linear with a tendency to reach a steady state for C-14 and C-16, when the pH in the donor compartment was 8.3. The transport kinetics for both ions studied were best fitted by an equation de rived from saturation kinetics that apply in reversible chemical reactions. The ion transfer rates increased as the pH in the donor compartment decrea sed. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.