Glycopeptides erythrocytes

Chemical-ionization, mass fragmentography was used for quantitative determination of variously linked monosaccharides in a study of the high-molecular-weight glycopeptide of erythrocytes.75 It appears... 

A feasible way of introducing acid-stable linkages into carbohydrates is N-deacetylation. This can be achieved with hydrazine.59,70,71 The use of sodium hydroxide-sodium benzenethioxide in aqueous dimethyl sulfoxide for this purpose has also been described72 The difference in the acid hydrolysis of N-acetylhexosamine-con-taining carbohydrates before and after N-deacetylation was used in the study of complex glycoprotein saccharides from human erythrocyte membranes.73-75 Methylation analysis of the glycopeptides prepared... 

Inhibitory Activity of Various Carbohydrates, Glycopeptides, and Glycoproteins in a Standard, 125I-Lectin-Erythrocyte Ghost-binding Assay866... 

In experiments designed to explore whether there is protein transverse asymmetry in membranes, it was shown that when trypsin was used to treat intact erythrocytes, the carbohydrate groups of tiie transmembrane protein glycophorin were released from the N-terminus of this protein (as glycopeptides). This was taken as evidence that the N-terminus of glycophorin must be on the exterior side of the membrane because ... 

Fia. 30. Gas-liquid chromatograms of the alditol acetates of the neutral sugars released after hydrolysis of various glycoproteins. Arabitol was added as the internal standard. (A) Orosomucoid (B) canine submaxillary mucin (C) a glycopeptide released by the action of trypsin from intact human erythrocytes. For GLC conditions see text. Reproduced from Lehnhardt and Winzier (LS) with permission. 

The sequence of amino acids around the glycosylated cysteine in human erythrocyte membrane glycopeptide is (Glc) 3-Ct/s-Glu-His-Ser-His-Asp-His-Gly-Ala-COOH (145), while in a glycopeptide isolated from urine the sequence is (Gal)2-Ct/s-Glu-His-Ser-His-Asp-Gly-Ala-COOH (144). Thus these glycosylated cysteine peptides are very similar. 

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