TABLE III. Identification of serpin-4 in SPC4s by MALDI-TOF mass spectrometry.
The mass spectral analysis was performed as described under “Experimental Procedures.” The measured monoisotopic (MH+) masses from SPC4s and their corresponding matching peptide from serpin-4 are shown. The peptides present only in isoform A or B of serpin-4 are indicated. A putative residue modification of a peptide is also indicated. α, one methionine oxidation; β, one cysteine carbamidomethylation by iodoacetamide; γ, one cysteine modification by acrylamide.
| Measured mass (MH+) from SPC4s |
Matched serpin-4 peptides |
Isoform A or B only | |||||
|---|---|---|---|---|---|---|---|
| SPC4-1 | SPC4-2 | SPC4-3 | SPC4-4 | SPC4-5 | Residues | Computed mass (MH+) | |
| 3266.655 | 3266.669 | 3266.739 | 3266.734 | 3266.687 | 29–59 | 3266.702 | |
| 852.443 | 852.436 | 852.441 | 61–67 | 852.469 | |||
| 1087.572 | 1087.581 | 1087.606 | 1087.615 | 1087.587 | 82–90 | 1087.615 | |
| 1203.619 | 1203.612 | 1203.639 | 1203.664 | 1203.634 | 99–108 | 1203.649 | |
| 1244.650 | 1244.654 | 1244.667 | 1244.689 | 1244.656 | 109–119 | 1244.689 | |
| 2752.324 | 2752.318 | 2752.374 | 2752.388 | 2752.334 | 120–143 | 2752.350 | A |
| 2768.321 | 2768.368 | 2768.374 | 2768.401 | 2768.335 | 120–143 | 2768.345 | Aβ, B |
| 1448.697 | 1448.679 | 1448.703 | 1448.717 | 1448.692 | 131–143 | 1448.702 | A |
| 1464.700 | 1464.680 | 131–143 | 1464.697 | B | |||
| 1186.618 | 1186.564 | 1186.584 | 1186.578 | 167–176 | 1186.655 | ||
| 1202.596 | 1202.594 | 1202.615 | 1202.640 | 1202.623 | 167–176 | 1202.650 | β |
| 1081.464 | 1081.453 | 1081.460 | 1081.489 | 1081.465 | 191–199 | 1081.478 | A |
| 1199.582 | 1199.616 | 1199.637 | 191–200 | 1199.563 | Bβ | ||
| 1354.643 | 1354.640 | 1354.666 | 1354.687 | 1354.635 | 200–210 | 1354.661 | |
| 1226.552 | 1226.539 | 1226.567 | 1226.594 | 1226.558 | 201–210 | 1226.566 | |
| 1242.543 | 1242.535 | 1242.554 | 1242.582 | 1242.554 | 201–210 | 1242.561 | β |
| 1139.550 | 1139.554 | 1139.586 | 1139.537 | 211–219 | 1139.567 | A | |
| 1127.508 | 1127.501 | 1127.535 | 1127.566 | 1127.510 | 211–219 | 1127.531 | B |
| 1155.532 | 1155.492 | 1155.510 | 1155.501 | 1155.446 | 211–219 | 1155.562 | Aβ |
| 1276.634 | 1276.624 | 1276.643 | 1276.668 | 1276.643 | 225–235 | 1276.654 | |
| 1549.682 | 1549.667 | 1549.698 | 1549.722 | 1549.689 | 258–269 | 1549.700 | |
| 1565.681 | 1565.656 | 1565.675 | 1565.700 | 1565.691 | 258–269 | 1565.695 | β |
| 2028.860 | 2028.851 | 2028.894 | 2028.920 | 2028.879 | 270–286 | 2028.886 | α |
| 2042.864 | 2042.871 | 2042.911 | 2042.941 | 2042.895 | 270–286 | 2042.902 | γ |
| 2793.352 | 2793.286 | 2793.343 | 2793.387 | 289–313 | 2793.344 | ||
| 2409.155 | 2409.125 | 2409.188 | 2409.212 | 2409.171 | 333–355 | 2409.179 | |