Figure 3.

Characterization of GEPO and receptor immunoprecipitation. (A) ζ-potential analysis of rHuEPO and GEPO. (B) SDS-PAGE electrophoresis suggested that the molecular weight of GEPO was not different from that of rHuEPO. Native PAGE electrophoresis demonstrated that GEPO, which was almost completely modified, formed a homogeneous band that moved towards the cathode faster than rHuEPO, indicating that this molecule has more negative charge. The single band of GEPO on native-PAGE also suggested that the glutaraldehyde reaction resulted in an intra-molecule crosslink derivative rather than an inter-molecule crosslink derivative. (C) Lysate protein from GEPO-treated P19 cells was precipitated with anti-EPOR. Left panel: the precipitate protein was reacted with IL3RB antibody and EPOR antibodies. Right panel: the precipitated protein was also detected with anti-EPO antibody with cross-reactivity for GEPO.