Interaction of nitrophenols with lipids at the air/water interface.

The uptake of ortho and para nitrophenol to charged and neutral lipid monolayers spread at the air/solution interface was studied by reflection spectroscopy. The adsorption characteristics of the two nitrophenols have been studied by measuring the surface pressure and surface potential as a function of molecular area of the different lipid monolayers in the presence of nitrophenols in the subphase. The results have been interpreted in terms of the electrostatic interaction between the negatively charged dissociated phenolate ions and the positively charged head group of dioctadecyldimethylammonium bromide monolayers

Interaction of insulin with lipid monolayers at the air/solution interface.

Interactions of insulin with lipid monolayers at the air/solution interface were studied by observing the kinetics of surface pressure change in the lipid monolayers at constant area and by spectroscopic techniques. The strong binding of insulin to positively-charged lipid monolayer resulted in increased surface pressure values, as well as in enhanced absorption and reflection signals in comparison to all other investigated lipid systems. This indicates that electrostatic interactions dominate these interactions

Adsorption of cytochrome c to phospholipid monolayers studied by reflection spectroscopy.

The uptake of cytochrome c by charged and neutral lipid monolayers was studied by using reflection spectroscopy. The method was shown to be a very sensitive and useful technique in studies of lipid-protein interactions. It was found that cytochrome c is preferentially bound to monolayers of negatively charged monolayers in the solid phase. Polarized light under oblique incidence was used to determine the average orientation of chromophores in cytochrome c bound to lipid monolayer. The transition moments of chromophore are oriented parallel to the monolayer plane