The Relative Net Negative Charge Due to Sialic Acid or Cross-Linked Glutamate on CHO-Derived SnRg Molecules Determined by Capillary Electrophoresis
| Enzyme/Chemical Treatment . | Cross-Linked Residue . | CE Mobility (10−6 cm2, V−1, min−1) . | Shift in Mobility From That of Native SnRg . |
|---|---|---|---|
| Mock digest | None | 5859 ± 54 | 0 |
| VC-sialidase | None | 4185 ± 29 | −1674 |
| NANase-I | None | 5013 ± 66 | −846 |
| VC-sialidase | Glutamate | 9478 ± 169 | 3619 |
| Meta-periodate | None | 5879 ± 17 | 20 |
| Enzyme/Chemical Treatment . | Cross-Linked Residue . | CE Mobility (10−6 cm2, V−1, min−1) . | Shift in Mobility From That of Native SnRg . |
|---|---|---|---|
| Mock digest | None | 5859 ± 54 | 0 |
| VC-sialidase | None | 4185 ± 29 | −1674 |
| NANase-I | None | 5013 ± 66 | −846 |
| VC-sialidase | Glutamate | 9478 ± 169 | 3619 |
| Meta-periodate | None | 5879 ± 17 | 20 |
The capillary electrophoretic mobilities for CHO-derived SnRg after the indicated treatments are shown. CE was performed in free solution using 50 mmol/L NaPO4 pH 7.4 and an uncoated capillary. Mobilities were determined relative to mesityl oxide, a neutral marker of electrosmotic flow. Greater CE mobility indicates a stronger electromigration toward the anode due to a greater negative charge to mass ratio. The sialic acid and glutamate-induced shifts were determined relative to the CE mobility of the native SnRg molecule. All reported values are the mean of triplicates ± 1 standard deviation (SD). Specificities of the glycosidases are NANase-1: a2-3 linked sialic acid, and VC sialidase: a2-3, -6, -8 linked sialic acid.