Figure 3.

Disulfide connectivity maps from a native IgG1 before (A) and after heat-stress (B), and residue-specific degree of disulfide scrambling observed in the heat-stressed IgG1 mAb (C). Native DSBs are represented by blue lines, and scrambled disulfides by red lines. In the heat-stressed sample (B), the DSB that links the LC and HC was subject to extensive scrambling and the native bond was no longer detectable. The degree of scrambling of cysteine residues in the heat-stressed adalimumab is shown in the histogram (C). Degree of scrambling varied significantly across the DSBs upon heat treatment: from 100% scrambling at the LC214 cysteine to virtually absent scrambling at HC429. The cysteines involved are coded by their residue number in the light or heavy chain, e.g., HC22 refers to the cysteine at residue 22 of the adalimumab HC.