Spectroscopic study of propofol binding to human serum albumin

Abstract

The interaction of propofol and human serum albumin (HSA) has been investigated by UV-absorption, fluorescence spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Propofol has shown a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constant (k) is estimated at a low value of 2.55×103 M−1 at 293K. FT-IR spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure in the amide regions I, II and III. The observed spectral changes of HSA-propofol complex indicate a larger intensity decrease in the absorption band of α-helix relative to that of β-sheets. This variation in intensity is related indirectly to the formation of H-bonding in the complex molecules, which accounts for the different intrinsic propensities of α-helix and β-sheets.