Effect of phase transition on the kinetics of dye transport in phospholipid bilater structures
Abstract
Binding of 8-anilino-1-naphthalenesulfonate to dimyristoyl-L-alpha-lecithin bilayers enhances the fluorescence quantum yield of the dye molecule by 100-fold. By following the generation of fluorescence after a rapid mixing in a stopped-flow apparatus (mixing time 2 msec), kinetics of the binding of the fluorescence probe to the phospholipid vesicles has been investigated in the temperature range where the crystal-liquid crystal phase transition of the bilayer structures occurs. No reactions depending on the dye or the vesicle concentrations were detected. This suggests that the initial adsorption of the dye was very rapid. Two kinetic phases which appear in the 50 msec and the second time ranges are unimolecular. The faster one has a small amplitude and is observable in the entire temperature range studied. In the phase transition region the slower reaction becomes the major kinetic phase. It also increases the apparent concentration of bound dye by a factor of 2. These observations suggest that the 50-msec reaction has detected a reorientation of the probe molecule after the initial binding, and that the slow reaction represents a transport of the dye molecule into the inner layer of the lipid vesicle. The transport reaction i...Continue Reading
Citations
Tocopheryl Succinate-Induced Structural Changes in DPPC Liposomes: DSC and ANS Fluorescence Studies.
Related Concepts
Related Feeds
Cell Biology of Lipids
Lipids are essential in many biological functions, including membrane structure, energy storage, and cell signaling. Find the latest research on the cell biology of lipids here.