Table 3.
Measured masses and average sodium ion adduction for four different glycoforms of holo-transferrin formed by nESI from aqueous solutions containing 10 mM ammonium bicarbonate (ABC) and 1 mM NaCl with no supercharging reagent, with 1.5% m-NBA, or with 2.5% sulfolane.
| Protein mass (Da) | |||||
|---|---|---|---|---|---|
| Protein glycoforms | 10 mM ABC | 10 mM ABC 1 mM NaCl |
+1.5% m-NBA | +2.5% sulfolane | Calculated mass |
| A | 79,714 ± 4 | 79,882 ± 21 | 79,944 ± 12 | 79,764 ± 5 | 79,700 Da |
| B | 79,848 ± 10 | 79,910 ± 15 | 79,846 Da | ||
| C | 80,372 ± 7 | 80,561 | 80,675 ± 21 | 80,425 ± 10 | 80,356 Da |
| D | 80,505 ± 12 | 80,567 ± 20 | 80,502 Da | ||
| Average # Na adducts | |||||
| 10 mM ABC |
10 mM ABC 1 mM NaCl |
+1.5% m-NBA | +2.5% sulfolane | ||
| A | 0.6 ± 0.2 | 8.3 ± 1.0 | 11.1 ± 0.6 | 2.9 ± 0.2 | |
| B | 0.1 ± 0.5 | 2.9 ± 0.7 | |||
| C | 0.7 ± 0.3 | 9.3 | 14.5 ± 1.0 | 3.1 ± 0.5 | |
| D | 0.1 ± 0.6 | 3.0 ± 0.9 | |||