Binding of sulfamerazine and sulfamethazine to bovine serum albumin and nitrogen purine base adenine: a comparative study

Quenching of bovine serum albumin (BSA) and DNA base (adenine) by sulfamerazine (SM) and sulfamethazine (SMT) was studied using UV-visible, fluorescence cyclic voltammetry and molecular docking methods. A strong fluorescence quenching reaction of SM and SMT to BSA/adenine was observed and the quenching mechanism was suggested as static. Both drugs can bind to BSA and adenine with stoichiometric ratio of 1:1 and the protein - drug complexes are stabilized mainly by hydrogen bonds and van der Waals interaction. Compared to SM, SMT contributes substantially higher binding efficiency with BSA/adenine. With addition of drug solution to the adenine/BSA, the oxidation and the reduction peaks shifted towards high and low potentials, respectively. R o, J, r and E values in the BSA-drugs are higher than that of adenine - drug molecules suggest that binding of the sulfa drugs with BSA is higher than adenine -drug molecules. Docking method specify that bioactive site of sulfa drugs moiety, the aniline group is interacted with the BSA molecules.