Table I.
Fragment ions detected in Q-TOF after tryptic digest of 1-FEH IIa, with calculated matches to theoretical digest of virtual cDNA derived protein, and confirmation of identity by tandem MS/MS sequencing
| Observed Mass | Charge State | Calculated Mass (Presumptive 1-FEH IIa Fragment Ion) | MS/MS Sequence (from N to C Terminus) |
|---|---|---|---|
| 415.2 | 2+ | 415.19 [T20+2H]2+ | 278 SFFDDAK 284 |
| 417.25 | 2+ | 417.22 [T40+2H]2+ | 467 SEEISLR 473 |
| 461.3 | 2+ | 461.26 [T47+2H]2+ | 533 FVVDQSVK 540 |
| 481.3 | 2+ | 481.26 [T36+2H]2+ | 427 VFQNQLGR 434 |
| 499.3 | 2+ | 499.26 [T35+2H]2+ | 419 EQSAIFFR 426 |
| 531.3 | 2+ | 531.27 [T1+2H]2+ | 1 QQIEQPYR 8 |
| 542.8 | 2+ | 542.79 [T5+2H]2+ | 107 QVQDLAWPK 115 |
| 559.8 | 2+ | 559.79 [T24+2H]2+ | 306 GWAGLQSFPR 315 |
| 585.3 | 2+ | 585.27 [T45+2H]2+ | 520 ISEMSAWSMK 529 |
| 621.3 | 2+ | 621.28 [T19+2H]2+ | 268 YDYGQFYASK 277 |
| 666.9 | 2+ | 666.87 [T33+2H]2+ | 402 GALGPFGLLAMASK 415 |
| 677.4 | 2+ | 677.36 [T34-35+2H]2+ | 416 DLKEQSAIFFR 426 |
| 829.4 | 2+ | 829.43 [T41+2H]2+ | 474 NLIDHSIIESFGAGGK 489 |
| 935.9 | 2+ | 935.95 [T39+2H]2+ | 450 SNIDTTSYGAFVDIDPR 466 |
| 1,066.5 | 2+ | No match | T6 N-linked glycopeptide:116 NLSDPFLR 123 (Deoxyhexose)1 (Pentose)1 (Man)3 (GlcNAc)2 |
| 691.3 | 3+ | 691.31 [T17+3H]3+ | AGFEGHDWYTLGTYSPDR |
| 892.05 | 3+ | No match | T6-T7 N-linked glycopeptide:116 NLSDPFLREWVK 127 (Deoxyhexose)1 (Pentose)1 (Man)3 (GlcNAc)2 |
| 950.14 | 3+ | 950.17 [T27-28+3H]3+ | QLIQWPVEEIEELRQNQVNLQNK |
| 1,234.25 | 3+ | No match | T44 N-linked glycopeptide:500 FVNNEEAHLFVFNNGTQNVK 519 (Hexose)3 (Man)3 (GlcNAc)2 |
Glycosylation sites NX(S/T) are presented in bold. The position of the fragments in the mature 1-FEH IIa protein are indicated.