Open AccessCell‐Free Synthesis and Glycosylatlon of the Major Human‐Red‐Cell Sialoglycoprotein, Glycophorin A
Author(s) -
JOKINEN Mikko,
ULMANEN Ismo,
ANDERSSON Leif C.,
KÄÄRIÄINEN Leevi,
GAHMBERG Carl G.
Publication year - 1981
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1981.tb05159.x
Subject(s) - glycophorin , sialoglycoprotein , sialoglycoproteins , biochemistry , microbiology and biotechnology , reticulocyte , glycoprotein , in vitro , chemistry , k562 cells , biology , membrane , messenger rna , gene
The human erythroid cell line, K562, synthesizes the major red cell sialoglycoprotein, glycophorin A. We have isolated an mRNA fraction which codes for glycophorin A from K562 cells and studied the synthesis of the sialoglycoprotein in a rabbit reticulocyte cell‐free system. In the absence of membranes a precursor form of glycophorin A was synthesized. This was identified using specific anti‐(glycophorin A) serum. The apparent molecular weight of the carbohydrate‐free precursor of glycophorin A wss 19500. This exceeds the molecular weight of the glycophorin A apoprotein by approximately 5000. In the presence of membranes from dog pancreas, the synthesized glycophorin A precursor was N ‐glycosylated and probably also O ‐glycosylated. The oligosaccharide chains remained incompleted and the glycoprotein synthesized in vitro corresponded to the glycosylated precursor of glycophorin A obtained in intact cells.