[Spectral study of the microenviroment change of aromatic amino-acid residues in BSA induced by pH].

The microenvironment change of aromatic amino-acid residues in BSA at various pH were studied by fluorescence spectra and ultraviolet absorption spectra. It suggested that the change of protein surface and surface hydrophobicity from result. Compared to neutral pH, the Trp microenvironment seemed to be more hydrophobic at lower pH indicating less local surface hydrophobicity of BSA. At higher pH, the protein undergo conformational changes and unhold, the more buried Phe exposed to solvents consistent with stronger surface hydrophobicity of BSA.