Interaction of acrylamide with bovine serum albumin

The binding of acrylamide (ACR) with purified bovine serum albumin (BSA) was studied. Binding of ACR with BSA was characterized by equilibrium dialysis, fluorescence studies, and ultraviolet spectroscopy. ACR was quantitated by high-pressure liquid chromatography. Equilibrium dialysis studies on the binding of ACR with BSA showed that more than 25% of the added ligand was bound to the protein at equilibrium. ACR produced a concentration-dependent decrease in uv absorbance of BSA, indicating reactivity of ACR with BSA. Fluorescence quenching studies of ACR binding showed a concentration-dependent quenching of the fluorescence of BSA. ACR also caused a concentration-dependent decrease in the fluorescence of sulfhydryl (-SH) groups present on BSA, implicating a role of protein -SH groups in the binding of ACR. Prior blocking of -SH groups by N-ethylmaleimide resulted in 16% inhibition of the initial binding of ACR, suggesting involvement of -SH groups. Our results demonstrate that ACR binds to BSA through both aromatic amino acids and -SH groups and that such binding may play an important role in pharmacodynamics and toxicity of ACR.