Triazine-human serum albumin association: thermodynamic approach and sodium effect

Human serum albumin (HSA) serves as a carrier protein to transport triazine herbicides to molecular targets. In this paper, a theoretical treatment was developed to describe the HSA-triazine herbicides association. A determination of the association constant, K, as well as the degree of complexation n(c) (the percent of complex guest) was carried out. Enthalpy-entropy compensation was also analyzed in relation to this mathematical model to confirm the herbicide complexation behavior with HSA. The role of the sodium cation (Na(+)) on this association was investigated. It was expected that the sodium ion would act on the herbicide-HSA association process by modifying the surface tension of the bulk solvent and increase the K and n(c) values. The results showed that for patients who suffer from Na(+) desequilibrium, the triazine-HSA binding would change and as well the toxicological effect of these herbicides.