Investigation of the interaction between pentachlorophenol and human serum albumin using spectral methods

The interaction between human serum albumin (HSA) and pentachlorophenol (PCP) was investigated by UV/vis absorption, circular dichroism (CD), fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. PCP effectively quenched the intrinsic fluorescence of HSA via static quenching. The process of binding PCP on HSA was a spontaneous molecular interaction procedure. The hydrophobic interaction played a major role in stabilizing the PCP–HSA complex. The distance r between donor and acceptor was obtained to be 3.35 nm according to Forster’s theory. The binding site of PCP to HSA mainly located within hydrophobic cavity between domain II and domain I. The effect of PCP on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy, CD and three-dimensional fluorescence spectra.