FIGURE 2.
Cysteine racemization on IgG1κ HC from control and stressed samples by peptide mapping. a, XIC of peptides from control and stressed samples and models peptides with corresponding isotopic distribution (inset). The y axis of the inset represents relative level. The peptide map is performed and run under disulfide reducing conditions. Top panel, unstressed antibody. Second panel from top, antibody was incubated at 56 °C for 6 days at pH 9.3 in D2O. Third panel from top, synthetic peptide S(l-C)DK, called l-H. Fourth panel from top, synthetic peptide S(d-C)DK (called d-H). Bottom panel, synthetic peptide SCisoDK. b, MS2 spectra of selected peaks shown in a.