Characterization of trisulfide modifications of recombinant antibodies by intact mass measurement and non-reduced peptide mapping

摘要

Trisulfide bonds were described as common modification of natural and recombinant antibodies of the IgG subtype [1]. They are formed by insertion of a sulfur atom into disulfide bonds. Here we described the formation of trisulfide bonds between heavy and light chains. Medium composition plays a key role in the formation of trisulfides. As described in literature, the concentration of cysteine and H2S are critical factors for the trisulfide formation [2]. By using cysteine-modified medium for fermentation trisulfide content of sample can be influenced. A MS peptide map method to quantify trisulfides was established for which a fixed pH is crucial to avoid inaccurate quantitation.