Table 3.
Identification of peptides by LC/MS/MS from LiCl-extracted cell-wall proteins of flax hypocotyl
| Mass range (kDa) | Protein identification | Species | Protein accession | Theoretical mass (kDa) | % coverage | Score | Peptide no. | Notes* |
|---|---|---|---|---|---|---|---|---|
| Control seedlings | ||||||||
| 55–60 | Unnamed protein product | Vitis vinifera | gi|27463662 | 60·188 | 7 | 206 | 3 | a |
| Pectinesterase | Solanum lycopersicum | gi|1944575 | 56·206 | 4 | 111 | 2 | ||
| 50–55 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 12 | 353 | 6 | |
| Os01g0312500 | Oryza sativa | gi|115436216 | 46·120 | 2 | 61 | 1 | b | |
| 34–36 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 1 | 188 | 4 | |
| Putative pectinesterase | Arabidopsis thaliana | gi|22531132 | 60·013 | 7 | 138 | 3 | ||
| Peroxidase (FlxPER3) | Linum usitatissimum | gi|1389835 | 38·171 | 1 | 134 | 3 | ||
| Anionic peroxidase (fragments) | Glycine max | gi|415474 | 31 | 63 | 1 | |||
| 30–34 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 22 | 487 | 8 | |
| Unnamed protein product | Vitis vinifera | gi|157340696 | 60·188 | 8 | 211 | 4 | c | |
| Peroxidase (FlxPER3) | Linum usitatissimum | gi|1389835 | 38·171 | 5 | 92 | 3 | ||
| Cd-treated seedlings | ||||||||
| 55–60 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 17 | 345 | 7 | |
| 50–55 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 26 | 521 | 9 | |
| 34–36 | Secreted glycoprotein (LuEP1) | Linum usitatissimum | gi|27463662 | 47·906 | 7 | 168 | 4 | |
| Peroxidase (FlxPER3) | Linum usitatissimum | gi|1389835 | 38·171 | 33 | 533 | 10 | ||
| 30–34 | Pectinesterase | Solanum lycopersicum | gi|1944575 | 56·206 | 4 | 131 | 2 | |
| Peroxidase (FlxPER3) | Linum usitatissimum | gi|1389835 | 38·171 | 15 | 293 | 5 | ||
| Putative pectin methylesterase (LuPME5) | Linum usitatissimum | gi|14582867 | 59·932 | 8 | 230 | 4 | ||
Proteins (60 µg from a mix of 10- and 18-d-old seedlings grown with or without Cd) were submitted to SDS–PAGE; after coloration with Comassie blue, the bands were excised and tryptically digested. The mass range of the band was estimated from the marker position. Theorical mass corresponded from the amino acid sequence without glycan.
* Notes corresponded to BLAST result: ‘a’, multicopper oxidase, putative (Ricinus communis), pectinesterase (Annona cherimola), sks5 (SKU5 Similar 5); copper ion binding/oxidoreductase (arabidopsis); ‘b’, pectin methylesterase (Musa acuminata) AAA group, pectinesterase-3 precursor, putative (Ricinus communis); ‘c’, pectinesterase (Annona cherimola), multicopper oxidase, putative (Ricinus communis).