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 nc (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 nc 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.