CE-SDS analysis of Etanercept using BioPhase 8800 system

CE-SDS analysis of Etanercept using BioPhase 8800 system

Introduction
 

Etanercept has been widely used in the treatment of plaque psoriasis, psoriatic arthritis, ankylosing spondylitis, and rheumatoid arthritis for over 20 years.1, 2 It works as a tumor necrosis factor (TNF) antagonist by binding to TNF molecules and preventing them from binding to the cell-bound receptors—which could otherwise lead to autoimmune disease when de-regulated TNF production occurs.3 Etanercept is a heavily glycosylated fusion protein consisting of the extracellular ligand-binding domain of human TNF receptor 2 (TNFR2) and the Fc domain of human IgG1.4 There are 2 N-glycosylation sites and 13 potential O-glycosylation sites on the TNFR2 domain and one N-glycosylation site on the Fc domain.4 The glycosylation alone represents approximately 30% of the total molecular weight of etanercept.5 The fusion protein is also a homodimer where disulfide bonds connect the two monomers. These properties combined make the protein structure very complex and highly heterogeneous. The physicochemical characterization of such molecules is very challenging.