SE-HPLC analysis for the papain-digested fragments of mAb-PFM monomer and HMW species following the protein A column fractionation. (A and D) The intact mAb-PFM monomer and HMW species, respectively. (B and C) The protein A column flow-through and the eluted fraction, respectively, of the digested mAb-PFM monomer. (E and F) The protein A column flow-through and the eluted fraction, respectively, of the digested mAb-PFM HMW species. The mobile phase was PBS.