3.2. SEC analysis
ORF8-CRM and ORF8-PEG were analyzed by a Superdex 200 column (1 cm × 30
cm). As shown in Fig. 2C, ORF8, CRM197, ORF8-CRM, and
ORF8-PEG were all eluted as a single peak, indicating the high purity.
The elution peaks of ORF8 and CRM197 were at 20.3 mL and
17.8 mL, respectively. As compared with ORF8 and CRM197,
the elution peaks of ORF8-CRM (15.8 mL) and ORF8-PEG (16.9 mL) were both
left-shifted. This indicated that conjugation with
CRM197 and self-conjugation with PEG could both increase
the hydrodynamic volume of ORF8.