Cysteine in cell culture media induces acidic IgG1 species by disrupting the disulfide bond network.

A high degree of charge heterogeneity is an unfavorable phenomenon commonly observed for therapeutic monoclonal antibodies (mAbs). Removal of these impurities during manufacturing often comes at the cost of impaired step yields. A wide spectrum of posttranslational and chemical modifications is known to modify mAb charge.