Table II.
Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF) peptide analysis of the NEC5 protein
| Peak No.
|
Mass
|
Amino Acid
|
||
|---|---|---|---|---|
| Observed | Predicted | Sequencea | Range | |
| 1 | 1,817.842 | 1,817.896 | TAWVETGSTIGELYYK | 136-151 |
| 2 | 1,668.856b, c | 1,668.870 | NYSSVLQFSIQNLR | 49-62 |
| 3 | 1,600.817 | 1,600.815 | LYAHMEPLVSTSPR | 444-457 |
| 4 | 1,445.685 | 1,445.688 | FEQMIFTPYGGR | 388-399 |
| 5 | 1,376.738 | 1,376.732 | GGGGNTFGLVLAWK | 222-235 |
| 6 | 1,324.636 | 1,324.635 | SMGEDLFWAIR | 211-221 |
| 7 | 1,277.647 | 1,277.648 | YGLAADNVIDAR | 187-198 |
| 8 | 1,175.623 | 1,175.631 | GLPPTLYSEAK | 351-361 |
| 9 | 1,097.613 | 1,097.563 | FPIYTTNNK | 40-48 |
| 10 | 1,057.588 | 1,057.579 | LHQDLYIR | 272-279 |
| 11 | b,d | 1,045.552 | NITINLDDK | 127-135 |
| 12 | b,d | 939.453 | GNTSYAQAK | 475-483 |
| 13 | 933.481 | 933.479 | VDPSNVFR | 504-511 |
| 14 | b,d | 904.473 | TLEQNATK | 253-260 |
| 15 | 897.463 | 897.447 | WQYVSSK | 265-271 |
| 16 | 888.477 | 888.479 | GESLDVLR | 341-348 |
| 17 | 870.444 | 870.447 | AAYINYR | 437-443 |
| 18 | 827.471 | 827.437 | ESSIHVR | 92-98 |
| 19 | 776.378 | 776.372 | LMDANGR | 199-205 |
| 20 | 665.299 | 665.300 | NNFDR | 492-496 |
| 21 | 610.344b,e | 610.320 | FNTTK | 63-67 |
| 22 | 602.387 | 602.366 | VWGIK | 484-488 |
a Predicted sites of N-glycosylation are shown in bold (peptides 2, 11, 12, 14, and 21). b Contains a predicted site of N-glycosylation. c Peptide observed only in NEC5a and NEC5b isoforms. dPeptide not observed in any of the NEC5 isoforms. e Peptide observed only in NEC5a isoform.