Table 1.
Measured and calculated molecular masses for conotoxin ɛ-TxlX
| Species | Molecular mass, Da
|
|
|---|---|---|
| Monoisotopic | Average | |
| Native | ||
| Observed | 1,929.46 | 1,931.97 |
| Calculated | 1,929.42 | 1,931.78 |
| Carbamidomethylated | ||
| Observed | 2,161.54 | 2,164.25 |
| Calculated | 2,161.53 | 2,164.02 |
The calculated molecular mass was based on the amino acid sequence: Gla Cys Cys Gla Asp Gly BrTrp Cys Cys Thr(GalNAc-Gal) Ala Ala HyPro, where Gla = γ-carboxyglutamic acid, BrTrp = 6-bromotryptophan, Thr(GalNac-Gal) = N-acetylgalactosamine and galactosamine attached to threonine, and HyPro = 4-hydroxyproline. All cysteine residues are disulfide-bonded. The monoisotopic and average observed molecular masses were acquired in reflector and linear modes, respectively.