Fig. 3. ESI mass analysis of the mAb and pBsAb prepared with different equivalents (5, 10, and 20) of cEBP-OPA. The data revealed that an average of 1.1 cyclic peptides was conjugated on the antibody when 5 equivalents of cEBP-OPA were added. An average of 2.4 cyclic peptides were conjugated on the antibody when 10 equivalents of cEBP-OPA were used, while the addition of 20 equivalents of cEBP-OPA resulted in a 9.6 peptide-to-antibody ratio.
