Sialoglycoprotein

A sialoglycoprotein is a combination of sialic acid and glycoprotein, which is, itself, a combination of sugar and protein.

Glycophorin C is one common sialoglycoprotein. Podocalyxin is another sialoglycoprotein found in the foot processes of the podocyte cells of the glomerulus in kidneys. Podocalyxin is negatively charged and therefore repels other negatively charged molecules thus contributing to the minimal filtration of negatively charged molecules by the kidney (needs citation)