The binding of desialylated glycoproteins by plasma membranes of rat liver
WE Pricer Jr, G Ashwell - Journal of Biological Chemistry, 1971 - Elsevier
WE Pricer Jr, G Ashwell
Journal of Biological Chemistry, 1971•ElsevierEvidence is presented to identify plasma membranes of liver as the major locus of binding
for circulating glycoproteins. The binding process involves a dual role for sialic acid in that its
presence on the membranes is essential, whereas its presence on the glycoprotein is
incompatible with binding. Enzymatic restoration of sialic acid residues onto partially
desialylated membranes is accompanied by increased binding activity and is suggestive of
the presence of an intrinsic membrane-associated sialyltransferase. In addition to the …
for circulating glycoproteins. The binding process involves a dual role for sialic acid in that its
presence on the membranes is essential, whereas its presence on the glycoprotein is
incompatible with binding. Enzymatic restoration of sialic acid residues onto partially
desialylated membranes is accompanied by increased binding activity and is suggestive of
the presence of an intrinsic membrane-associated sialyltransferase. In addition to the …
Evidence is presented to identify plasma membranes of liver as the major locus of binding for circulating glycoproteins. The binding process involves a dual role for sialic acid in that its presence on the membranes is essential, whereas its presence on the glycoprotein is incompatible with binding. Enzymatic restoration of sialic acid residues onto partially desialylated membranes is accompanied by increased binding activity and is suggestive of the presence of an intrinsic membrane-associated sialyltransferase.
In addition to the requirement for sialic acid, the binding of proteins by plasma membranes exhibits an absolute dependence upon the presence of calcium. Changes in the concentration of this ion, within the pH range of 6.0 to 7.8, result in a rapid reversal of the binding process and provide a model system for the study of protein uptake and transport by the intact liver cell.
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