Figure 6. Third deamidation of GlyAsnAsnAsnGly

The first-order deamidation rate curve for the third deamidation of GlyAsnAsnAsnGly, using deamidation of the second doubly deamidated peak. This figure is ln[C/(C+D)] versus time. The measured deamidation half-time is 84 days. The linearity and deamidation intercept of the plot demonstrates that this deamidation has been separately measured with moderate accuracy by the mass defect ICR FTMS technique. Heterogeneity arising from earlier deamidations and the longer deamidation half-time as compared with the sampling interval have diminished this accuracy as compared with that of the first two deamidations.