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.