Table 2.
Identification of deamidation sites in the 26 synthetic peptides overlapping the entire sequence of the recombinant α-gliadin by nanoESI-MS/MS experiments
| Theoretical MW | Precursor ion (MH33+) | Peptide | Sequence | Deamidation | Modified Q |
| 2296.192 | 767.06 | 1–20 | VRVPVPQLQPQNPSQQQPQE | 2 | 7/11 |
| 2328.146 | 777.71 | 10–29 | PQNPSQQQPQEQVPLVQQQQ | 2 | 21/16 |
| 2335.196 | 780.40 | 20–39 | EQVPLVQQQQFLGQQQPFPP | 3 | 21/27 or 28/34 |
| 2368.164 | 791.09 | 30–49 | FLGQQQPFPPQQPYPQPQPF | 2 | 34/40 |
| 2411.191 | 805.06 | 40–59 | QQPYPQPQPFPSQQPYLQLQ | 1 | 52 |
| 2355.19 | 786.63 | 50–69 | PSQQPYLQLQPFPQPQLPYS | 2 | 52/65 |
| 2376.201 | 793.75 | 60–79 | PFPQPQLPYSQPQPFRPQQP | 1 | 65 |
| 2438.171 | 814.40 | 70–89 | QPQPFRPQQPYPQPQPQYSQ | 2 | 77/86 |
| 2397.135 | 800.70 | 80–99 | YPQPQPQYSQPQQPISQQQQ | 2 | 86/91 |
| 2461.169 | 90–109 | PQQPISQQQQQQQQQQQQQQ | 0 | ||
| 2549.233 | 100–119 | QQQQQQQQQQQQQQQQILQQ | * | ||
| 2436.260 | 110–129 | QQQQQQILQQILQQQLIPCM | * | ||
| 2303.210 | 769.45 | 120–139 | ILQQQLIPCMDVVLQQHNIA | 1 | 123 or 124 |
| 2256.172 | 130–149 | DVVLQQHNIAHGRSQVLQQS | 0 | ||
| 2324.125 | 766.04 | 141–160 | GRSQVLQQSTYQLLQELCCQ | 1 | 148 |
| 2459.161 | 150–169 | TYQLLQELCCQHLWQIPEQS | 0 | ||
| 2408.217 | 160–179 | QHLWQIPEQSQCQAIHKVVH | 0 | ||
| 2349.281 | 784.01 | 170–189 | QCQAIHKVVHAIILHQQQKQ | 0 | |
| 2322.208 | 775.40 | 180–199 | AIILHQQQKQQQQPSSQVSF | 1 | 191 |
| 2287.123 | 764.04 | 190–209 | QQQPSSQVSFQQPLQQYPLG | 2 | 200/205 |
| 2300.132 | 768.04 | 200–219 | QQPLQQYPLGQGSFRPSQQN | 1 | 205 |
| 2168.031 | 724.01 | 210–229 | QGSFRPSQQNPQAQGSVQPQ | 1 | 223 |
| 2293.140 | 766.05 | 220–239 | PQAQGSVQPQQLPQFEEIRN | 2 | 223/230 |
| 2314.181 | 230–249 | QLPQFEEIRNLALQTLPAMC | 0 | ||
| 2223.114 | 240–259 | LALQTLPAMCNVYIPPYCTI | 0 | ||
| 2116.034 | 250–268 | NVYIPPYCTITPFGIFGTN | 0 |
* Peptides not analyzed due to solubility problem are indicated with an asterisk. It was not possible to define which of the underlined Q residues is deamidated in peptides 20–39 and 120–139.