Table 2.
. Tryptic Peptide Peaks of BSA modified with IAA or 13C6-IAA (BSA-IAA: BSA-13C6-IAA=1:1)
| Number of Peptides | Observed m/z Value of IAA Modified Peptide | Observed m/z Value of 13C6IAA Modified Peptide | Theoretical1)m/z Value of Unmodified Peptide | Identified Peptide from Database | Number of Cysteines | Number of Adding IAAs (13C6IAAs) | |
|---|---|---|---|---|---|---|---|
| Position on Protein | Sequence | ||||||
| 1 | 1655.3 | 1661.3 | 11 522.3 | unknown | unknown | unknown | 1 |
| 2 | 1974.5 | 1980.5 | 11 841.5 | 483–489 | LCVLHEK | 1 | 1 |
| 3 | 1110.5 | 1116.5 | 1 977.5 | 123–130 | NECFLSHK | 1 | 1 |
| 4 | 1144.5 | 1150.5 | 1011.4 (low)2) | 413–420 | QNCDQFEK | 1 | 1 |
| 5 | 1148.6 | 1154.5 | 11 1015.5 | 310–318 | SHCIAEVEK | 1 | 1 |
| 6 | 1157.6 | 1163.6 | 11 1024.5 | 499–507 | CCTESLVNR | 2 | 1 |
| 7 | 1290.6 | 1302.7 | 11 1024.5 | 499–507 | CCTESLVNR | 2 | 2 |
| 8 | 1183.7 | 1189.6 | 1050.5 (low) | 588–597 | EACFAVEGPK | 1 | 1 |
| 9 | 1185.6 | 1191.7 | 1052.5 (low) | 460–468 | CCTKPESER | 2 | 1 |
| 10 | 1318.7 | 1330.6 | 1052.5 (low) | 460–468 | CCTKPESER | 2 | 2 |
| 11 | 1443.8 | 1455.8 | 1177.6 (ND)3) | 300–309 | ECCDKPLLEK | 2 | 2 |
| 12 | 1615.8 | 1627.8 | 1349.5 (ND) | 76–88 | TCVADESHAG CEK | 2 | 2 |
| 13 | 1495.9 | 1501.7 | 1362.7 (ND) | 89–100 | SLHTLFGDE CK | 1 | 1 |
| 14 | 1630.8 | 1642.7 | 1364.5 (ND) | 106–117 | ETYGDMAD CCEK | 2 | 2 |
| 15 | 1519.8 | 1525.7 | 1386.6 (ND) | 286–297 | YICDNQDTISSK | 1 | 1 |
| 16 | 1654.8 | 1666.9 | 1388.6 (ND) | 375–386 | EYEATLE CCAK | 2 | 2 |
| 17 | 1630.8 | 1636.7 | 1497.6 (ND) | 387–399 | DDPHACYSTVFDK | 1 | 1 |
| 18 | 1652.9 | 1658.8 | 1519.7 (ND) | 139–151 | LKPDPNTLC DEFK | 1 | 1 |
| 19 | 1844.9 | 1856.8 | 1578.6 (ND) | 267–280 | ECCHGDLL CADDR | 3 | 2 |
| 20 | 1977.8 | 1995.8 | 1578.6 (ND) | 267–280 | ECCHGDLL CADDR | 3 | 3 |
| 21 | 1899.8 | 1911.8 | 1633.7 (ND) | 184–197 | YNGVFQ CC QAEDK | 2 | 2 |
| 22 | 1801.0 | 1806.9 | 1667.8 (ND) | 469–482 | MPCTEDYLSLILN | 1 | 1 |
| 23 | 1817.0 | 1823.0 | 1683.8 (ND) | 469–482 1Met-Ox4) | MPCTEDYLSLILN | 1 | 1 |
| 24 | 1854.9 | 1860.9 | unknown | unknown | unknown | 1 | |
| 25 | 1882.9 | 1889.0 | 1749.9 (ND) | unknown | unknown | unknown | 1 |
| 26 | 1889.0 | 1894.8 | 1756.0 (ND) | unknown | unknown | unknown | 1 |
| 27 | 2155.9 | 2174.0 | 1756.7 (ND) | 581–597 | CCAADDKEA CFAVEGPK | 3 | 3 |
| 28 | 1957.0 | 1963.0 | 111823.9 | 508–523 | RPCFSALTPDETYVPK | 1 | 1 |
| 29 | 2534.3 | 2540.3 | 2401.2 (ND) | 319–340 | DAIPENLPPLTADFAEDKDV CK | 1 | 1 |
1)
Theoretical m/z Value of Unmodified Peptide: calculated from the peptide sequence or the observed m/z value of IAA/13C6-IAA modified peptides.
2)
low: low intensity.
3)
ND: not detectable.
4)
Met-Ox; methionine is oxidized.