title: Investigation of the interaction of Mercurochrome constituents with proteins using liquid chromatography/mass spectrometry.
abstract: The interaction of Mercurochrome, a medical preparation based on the mercury organic compound merbromin, with free thiols in low molecular weight peptides and in proteins has been investigated by means of liquid chromatography (LC) and electrospray mass spectrometry (ESI-MS). Beta-lactoglobulin A (beta-LGA) from bovine milk (18.4 kDa) has been used as the model protein. It was found that, in contrast to assumptions in literature, the commercial product itself is a heterogeneous mixture of moderate chemical stability, which may contain precipitated Hg salts depending on storage time and conditions. Further variability results from different degrees of bromination of the fluorescein backbone of the compound. The formation of mercury compound-protein adducts was detected. The peptide sequence T13 containing a free thiol residue was identified as the binding site for mercury species after tryptic digestion of beta-lactoglobulin A. While fresh Mercurochrome tends to the formation of a Hg(II)-beta-LGA adducts due to excess Hg(2+) in solution, investigations after precipitation of Hg salts yield Hg(merbromin)(beta-LGA) as the major product.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstr. 30, 48149 Münster, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Wilken
authors.forename: Rasmus
authors.initials: R
authors.lastname: Janzen
authors.forename: Michael
authors.initials: M
authors.lastname: Holtkamp
authors.forename: Sascha
authors.initials: S
authors.lastname: Nowak
authors.forename: Michael
authors.initials: M
authors.lastname: Sperling
authors.forename: Martin
authors.initials: M
authors.lastname: Vogel
authors.forename: Uwe
authors.initials: U
authors.lastname: Karst
mesh_terms: D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods*; D007782:Lactoglobulins / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D008622:Merbromin / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D007782:Lactoglobulins; D008622:Merbromin