Spectroscopic investigations of pentobarbital interaction with human serum albumin

The interaction between pentobarbital and human serum albumin has been investigated. The basic binding interaction was studied by UV-absorption and fluorescence spectroscopy. From spectral analysis pentobarbital showed a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constant (k) is estimated at 1.812 x 10(4) M-1 at 293 K. FT-IR spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure and drug binding mechanisms. The observed spectral changes of HSA-pentobarbital complex indicate a larger intensity decrease in the absorption band of alpha-helix relative to that of beta-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 alpha-helix and beta-sheets. (c) 2009 Elsevier B.V. All rights reserved.