Multi-Spectroscopic Investigation of the Interactions between Cholesterol and Human Serum Albumin

Abstract

The interaction between cholesterol and human serum albumin has been investigated. The basic binding interaction was studied by UVabsorption and fluorescence spectroscopy. From spectral analysis cholesterol showed a strong ability to quench the intrinsic fluorescence of HSA through a static quenching mechanism. The binding constant (k) is estimated to be K=0.214 × 104 M-1 at 293 K. FTIR spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure and cholesterol binding mechanisms. The observed spectral changes indicate a higher percentage of H-bonding between cholesterol and a-helix (secondary structure motif in HSA) compared to the percentage of H-bonding between cholesterol and b-sheets (secondary structure motif in HSA)