title: Methyl acceptors for protein methylase II from human-erythrocyte membrane.
abstract: Membrane proteins from human erythrocytes were methylated with purified protein methylase II (S-adenosylmethionine:protein-carboxyl O-methyltransferase, EC.2.1.1.24). The methylated proteins were analyzed by dodecyl sulfate/polyacrylamide gel electrophoresis. Monomeric and dimeric glycophorin A (NaIO4/Schiff-2 and NaIO4/Schiff-1 positive bands) and 'band 4.5' were identified as two major classes of methyl-acceptor polypeptides for protein methylase II. In rabbit erythrocyte membrane where glycophorin A is absent, 'band 4.5' was the only major methyl-acceptor protein component. Extracted and purified glycophorin A from human erythrocytes was also found to be an excellent substrate for protein methylase II with a Km of 35.7 microM. The role of erythrocyte membrane protein methylation is discussed with regard to membrane function.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000032:analysis*; D004912:Erythrocytes / Q000032:analysis* / Q000201:enzymology; D006021:Glycophorins / Q000302:isolation & purification; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000097:blood*; D008745:Methylation; D011496:Protein Methyltransferases / Q000378:metabolism*; D011497:Protein O-Methyltransferase / Q000378:metabolism*; D011817:Rabbits
chemical_list: D006021:Glycophorins; D008565:Membrane Proteins; D011496:Protein Methyltransferases; D011497:Protein O-Methyltransferase