Fluorescence spectroscopy studies on 5-aminosalicylic acid and zinc 5-aminosalylicylate interaction with human serum albumin.

The interaction between 5-aminosalicylic acid (5-ASA) or zinc 5-aminosalylicylate (5-ASZ) and human serum albumin (HSA) was studied by fluorescence spectroscopic technique. The binding constants of 5-ASA or 5-ASZ with HSA were determined at different temperatures under the optimum conditions. The binding sites were obtained and the acting force were suggested to be mainly hydrophobic. The effect of common ions on the binding constants was also investigated. A fluorescence spectroscopy assay of the proteins is presented in the paper. The determination results of the proteins in human serum by this method are very close to those obtained using Coomassie Brilliant Blue G-250 colorimetry, with relative standard deviations of 0.8-2.9%. A practical method was proposed for the determination of 5-ASA or 5-ASZ in human serum samples.