Figure 4.

Overview of the neo-N termini in heavy chain 2 after proteolytic treatment. A summary of the N-terminal sequencing results and LC-MS/MS data are given in Table 1. The schematics represent HC2 with the location of the neo-N termini indicated with vertical lines, and the relevant protease is indicated. The major and initial cleavage sites are located in the C terminus close to the PGP cross-link. Cleavage in the C terminus of HC2 releases HC2 from the IαI complex and is likely to facilitate HC2/TSG-6 activity and increase the rate of the HC transfer reaction.