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.