Table 1.
Carbohydrate composition of normal and Gerbich-negative glycophorin C before and after N-deglycosylation
| Sample | Sugar composition (relative molar ratios)* |
||||
|---|---|---|---|---|---|
| GalNAc | GlcNAc | Gal | Man | NeuNAc | |
| Normal glycophorin C | 11.4 | 6.0 | 13.1 | 3.0 | 20.5 |
| N-deglycosylated normal glycophorin C | 11.8 | 1.7 | 12.1 | ND | 18.2 |
| N-linked glycans of normal glycophorin C | ND | 4.8 | 1.9 | 3.0 | 1.8 |
| Gerbich-negative glycophorin C | 4.8 | 2.9 | 5.8 | 8.0 | 6.7 |
| N-deglycosylated Gerbich-negative glycophorin C | 5.0 | 0.2 | 4.9 | ND | 5.6 |
| N-linked glycans of Gerbich negative glycophorin C | ND | 2.5 | 1.1 | 7.8 | 0.9 |
Untreated glycophorin C, N-deglycosylated glycophorin C, and N-linked glycans released by treatment of glycophorin C with N-glycanase were hydrolyzed with either 2.5 M trifluoroacetic acid (to release neutral sugars and hexosamines) or 2 M acetic acid (to release sialic acid). The hydrolysates were dried, and the sugars were analyzed by high-pH anion-exchange HPLC. ND, not detected.
*The sugars in the hydrolysates were quantitated from the chromagraphic peak areas and by using standard sugar solutions.