<Tr> <Td> Incubation of cultured cells with glycoproteins as radioactive decay bands </Td> <Td> Leads to detection of a radioactive sugar after electrophoretic separation . </Td> </Tr> <Tr> <Td> Treatment with appropriate endo - or exoglycosidase or phospholipases </Td> <Td> Resultant shifts in electrophoretic migration help distinguish among proteins with N - glycan, O - glycan, or GPI linkages and also between high mannose and complex N - glycans . </Td> </Tr> <Tr> <Td> Agarose - lectin column chromatography, lectin affinity chromatography </Td> <Td> To purify glycoproteins or glycopeptides that bind the particular lectin used . </Td> </Tr> <Tr> <Td> Lectin affinity electrophoresis </Td> <Td> Resultant shifts in electrophoretic migration help distinguish and characterize glycoforms, i.e. variants of a glycoprotein differing in carbohydrate . </Td> </Tr>

What is the function of the glycoprotein in the cell membrane