Effect of endo-beta-galactosidase on intact human erythrocytes.
Endo-beta-galactosidase, a glycosidase that hydrolyzes Gal beta 1-4 GlcNAc linkages in glycoconjugates, has been used to probe the plasma membrane of human erythrocytes. Coomassie blue staining of stroma components separated by sodium dodecyl sulfate-acrylamide gel electrophoresis indicates that treatment of red cells with endo-beta-galactosidase converts Protein 3, the anion transporter of the erythrocyte, to a more compact staining band. No other components detected by Coomassie staining are affected. Following labeling of red cells with galactose oxidase + NaB3H4, 45 to 50% of the [3H]galactose residues can be released by endo-beta-galactosidase. In contrast, only 5% of the label incorporated by treatment with periodate + NaB3H4, can be removed. [3H]Galactose residues are released from three components: Protein 3, Band 4.5, and the megaloglycolipids. The susceptibility of these components to endo-beta-galactosidase, together with the high content of Gal and GlcNAc present in Protein 3 and the megaloglycolipids, suggests that the erythrocyte membrane contains several components with N-acetyllactosamine repeating units, a structure commonly found in connective tissue glycoconjugates.
D004910:Erythrocyte Membrane / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D005692:Galactose Oxidase; D005696:Galactosidases; D006017:Glycolipids / Q000097:blood*; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D008563:Membrane Lipids / Q000097:blood*; D008565:Membrane Proteins / Q000097:blood*; D008970:Molecular Weight; D001616:beta-Galactosidase
D006017:Glycolipids; D006023:Glycoproteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D005692:Galactose Oxidase; D005696:Galactosidases; D001616:beta-Galactosidase