NMR kinetic studies of the ionophore X-537A-mediated transport of manganous ions across phospholipid bilayers |
| |
Authors: | Hadassa Degani |
| |
Institution: | Isotope Department, Weizmann Institute of Science, Rehovot, Israel |
| |
Abstract: | Nuclear magnetic resonance spectroscopy has been applied as a method for studying manganous ions transport across the membrane of phosphatidylcholine vesicles. The rates of the ionophore X-537A (lasalocid A)-mediated Mn2+ transport have been measured as a function of ionophore concentration, pH of the vesicle suspension, and temperature. The translocation was found to occur via a neutral complex composed of one manganous ion bound to two ionized X-537A molecules (Mn X2). The activation energy for the overall transport process was determined to be 22 ± 5 kcal/mol. Also a pKa of 5.0 ± 0.2 was determined for the ionophore acid dissociation equilibrium in the vesicle suspension. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|