Structure determination of the single glycan of rabbit serotransferrin by methylation analysis and 360 MHz 1H NMR spectroscopy

The glycopeptide fraction of rabbit serotransferrin (STF) has been investigated applying an original method for the determination of glycan primary structure combining monosaccharide determination, permethylation and 360 MHz 1H NMR. It is concluded that the highly purified rabbit transferrin contains only 1 glycan chain/molecule. A heterogeneity of the glycan moiety in the sialic acid residues was observed on isolation by paper electrophoresis of a disialylglycopeptide G-1 and a monosialylglycopeptide 2. The primary structure of glycopeptide G-1 deduced on the basis of the data of carbohydrate composition, permethylation analysis and 360 MHz 1H NMR spectroscopy is identical to the primary structure of human serotransferrin glycan and the glycopeptide G-2 was shown by 1H NMR spectroscopy, to be a mixture of two isomeric monosialylglycopeptides. (Auth.)