The physical interaction of antithyroid drug, propylthiouracil was studied with bovine and human serum albumins through UV absorption and fluorescence spectroscopic techniques. The obtained values of the quenching constants were calculated by the Stern-Volmer equation are in the order of 1012 Lmol-1 s-1 indicating that both serum albumins were quenched by the drug in a static manner. The binding constants of the drug interaction with both HSA and BSA proteins are found to be relatively weak and are in the order of 103 M-1. The tryptophan residues of HSA and BSA are most perturbed by the binding process which was authenticated by the fluorescence spectra of both proteins in the presence of propylthiouracil. The importance behind this study is to clarify the mechanism of the interaction between propylthiouracil with HSA and BSA, as well as providing additional values in order to study drug-protein interaction which may facilitate the study of drug metabolism and transportation.
Husain Alsamamra, Musa Abuteir and Saqer Darwish