Fetuin and asialofetuin at charged surfaces: Influence of sialic acid presence

Abstract

Major human diseases are associated with changes in glycosylation. The sialic acid is highly expressed saccharide residue typically terminating branches of protein glycans and glycosphingolipids. Here we compared sialoprotein fetuin with its desialylated form – asialofetuin using label-free constant current chronopotentiometric stripping (CPS) analysis and impedance C-t curves to better understand the behavior of glycoproteins at charged surfaces. Electrochemistry represents useful tool for study of molecules at charged surfaces. Using CPS peak H, we show that the terminal sialic acids presence in glycans of fetuin stabilizes its molecule against effects of electric field. Additionally the presence of negatively charged sialic acid prevents an interaction between glycoprotein and negatively charged electrode. The different behavior of the glycoproteins according to sialic acid content can also be used for easy determination of sialoglycoproteins.