Figure 3

PEGylation process and purification of PEG-GCSF. (A) Schematic overview of PEGylation for GCSF and purification of PEG-GCSF. (B) SDS-PAGE analysis of GCSF and PEG-GCSF showed monoPEG was conjugated to 1 GCSF molecule. M, molecular weight marker; lane 1, GCSF before PEGylation (18.8 kDa), lane 2, PEG-GCSF after PEGylation step with mPEG-CHO and purification through SP chromatography (38.8 kDa). (C) Chromatogram of HiTrap SP HP column to obtain pure PEG-GCSF. PEG-GCSF with higher negative charge was eluted before GCSF.