The characterizing of the interaction of amphotericin B with cholesteryl esters

Amphotericin B has been widely applied as a probe for sterol location in biological membrane since an alteration of its adsorption spectrum is induced by formation of sterol-polyene antibiotic complex. The binding of amphotericin B to cholesterol, cholesteryl oleate and cholesteryl linoleate has been investigated using absorbance measurements and the results have been rationalized assuming a system 1:1 drug - steroid. The binding constant of amphotericin B to cholesterol, cholesteryl oleate and cholesteryl linoleate has been determined using different methods: Benesi-Hildebrand, Scott and Scatchard. The differences in values of binding parameters are due to the small structural differences between cholesterol, cholesteryl oleate and cholesteryl linoleate molecules.