Table 1.
Identification of tTGase-modified peptides by MALDI-MS and definition of the deamidated glutamine residues present in the recombinant α-gliadin by nanoESI-MS/MS experiments
| MH+ | Precursor ion | Peptide | Deamidation | Sequence |
| 1560.88 | 780.96 MH22+ | 1–14 | 2 | VRVPVPQ*LQPQ*NPS |
| 2738.49 | 913.49 MH33+ | 1–24 | 4 | VRVPVPQ*LQPQ*NPSQQ*QPQEQ*VPL |
| 3497.85 | 950.00 MH44+ | 1–30 | 5 | VRVPVPQ*LQPQ*NPSQQ*QPQEQ*VPLVQQQQF |
| 1461.82 | 731.45 MH22+ | 2–14 | 2 | RVPVPQ*LQPQ*NPS |
| 2925.35 | 975.76 MH33+ | 31–55 | 3 | LGQQ*QPFPPQ*QPYPQPQPFPSQ*QPY |
| 2295.11 | 765.72 MH33+ | 32–51 | 2 | GQQ*QPFPPQ*QPYPQPQPFPS |
| 1569.84 | 785.47 MH22+ | 56–68 | 1 | LQLQPFPQPQ*LPY |
| 1404.75 | 702.87 MH2+2+ | 56–67 | 0 | LQLQPFPQPQLP |
| 1455.74 | 728.37 MH22+ | 57–68 | 1 | QLQPFPQPQ*LPY |
| 2149.09 | 717.03 MH33+ | 69–86 | 1 | SQPQPFRPQ*QPYPQPQPQ |
| 3092.55 | 1031.51 MH33+ | 69–94 | 3 | SQPQPFRPQ*QPYPQPQPQ*YSQPQ*QPI |
| 2312.13 | 771.33 MH33 | 70–88 | 1 | QPQPFRPQ*QPYPQPQPQYS |
| 1464.75 | 732.87 MH22+ | 75–86 | 1 | RPQ*QPYPQPQPQ |
| 2408.22 | 803.41 MH33+ | 75–94 | 3 | RPQ*QPYPQPQPQ*YSQPQ*QPI |
| 960.49 | 959.49 MH+ | 87–94 | 1 | YSQPQ*QPI |
| 1386.72 | 693.86 MH22+ | 95–105 | 0 | SQQQQQQQQQQ |
| 3262.47 | 816.37 MH44+ | 95–120 | 0 | SQQQQQQQQQQQQQQQQQQQQILQQI |
| 1311.72 | 656.87 MH22+ | 118–128 | 1 | QQILQQQLIPC |
| 943.63 | 942.63 MH+ | 121–128 | 1 | LQQQLIPC |
| 1267.67 | 634.34 MH22+ | 129–139 | 0 | MDVVLQQHNIA |
| 1592.83 | 796.83 MH22+ | 198–211 | 2 | SFQ*QPLQQ*YPLGQG |
| 1591.82 | 531.27 MH33+ | 199–212 | 1 | FQQPLQQ*YPLGQGS |
| 1444.73 | 722.86 MH22+ | 200–212 | 1 | QQPLQQ*YPLGQGS |
| 889.45 | 445.23 MH22+ | 204–211 | 0 | QQYPLGQG |
| 1444.71 | 722.85 MH22+ | 212–224 | 0 | SFRPSQQNPQAQG |
| 1531.74 | 766.87 MH22+ | 212–225 | 0 | SFRPSQQNPQAQGS |
| 1984.99 | 662.34 MH33+ | 212–229 | 1 | SFRPSQQNPQAQ*GSVQPQ |
| 2970.50 | 990.84 MH33+ | 212–237 | 2 | SFRPSQQNPQAQ*GSVQPQQ*LPQFEEI |
| 1456.76 | 728.88 MH22+ | 226–237 | 1 | VQPQQ*LPQFEEI |
| 1096.67 | 548.84 MH22+ | 238–247 | 0 | RNLALQTLPA |
| 2351.10 | 784.36 MH33+ | 248–268 | 0 | MCNVYIPPYCTITPFGIFGTN |
The deamidation sites are indicated with an asterisk. It was not possible to define which of the underlined Q residues is deamidated in peptide 1–30 and 118–128.