Interaction of thimerosal with proteins—ethylmercuryadduct formation of human serum albumin and β-lactoglobulin A

Abstract

The interaction of thimerosal, an ethylmercury-containing bactericide and fungicide used as preservative in vaccines and other drugs, with free thiols in proteins has been investigated using gradient reversed phase liquid chromatography (LC) with inductively coupled plasma mass spectrometry (ICP-MS) and electrospray mass spectrometry (ESI-MS) detection. As model proteins, β-lactoglobulin A (18.4 kDa) from bovine milk and human serum albumin (66.5 kDa) have been used. Physiological conditions upon an intravenous injection of thimerosal-containing drugs were mimicked. The formation of ethylmercury–protein adducts was proved and the identification of the binding site of ethylmercury, a free thiol residue in the peptide T13 was achieved after tryptic digestion of β-lactoglobulin A.