Table 4. Detailed mass spectrometric analysis of L-FABP.
| m/z submitted | MH+ matched | Delta (ppm) | Modifications | Start | End | Missed cleavages | Database sequence |
|---|---|---|---|---|---|---|---|
| 1210.70 | 1210.70 | 0 | 21 | 31 | 0 | AIGLPEELIQK | |
| 1442.77 | 1442.78 | 5 | 37 | 49 | 1 | GVSEIVQNGKHFK | |
| 1752.00 | 1752.03 | 17 | 21 | 36 | 2 | AIGLPEELIQKGKDIK | |
| 1762.79 | 1762.81 | 12 | 7 | 20 | 0 | YQLQSQENFEAFMK | |
| 1778.80 | 1778.81 | 1 | 1Met-ox | 7 | 20 | 0 | YQLQSQENFEAFMK |
| 1791.92 | 1791.99 | 38 | 81 | 96 | 1 | TVVQLEGDNKLVTTFK | |
| 2019.12 | 2019.15 | 16 | 79 | 96 | 2 | VKTVVQLEGDNKLVTTFK | |
| 2147.11 | 2147.21 | 47 | 81 | 99 | 2 | TVVQLEGDNKLVTTFKNIK | |
| 2248.15 | 2248.21 | 28 | 37 | 57 | 2 | GVSEIVQNGKHFKFTITAGSK | |
| 2311.11 | 2311.07 | 18 | AcetN | 1 | 20 | 1 | SFSGKYQLQSQENFEAFMK |
| 2327.12 | 2327.07 | 25 | AcetN 1Met-ox | 1 | 20 | 1 | SFSGKYQLQSQENFEAFMK |
| 2381.13 | 2381.23 | 41 | 100 | 121 | 0 | SVTELNGDIITNTMTLGDIVFK | |
| 2443.06 | 2443.10 | 18 | 58 | 78 | 0 | VIQNEFTVGEECELETMTGEK | |
| 2537.33 | 2537.33 | 0 | 100 | 122 | 1 | SVTELNGDIITNTMTLGDIVFKR | |
| 2553.28 | 2553.32 | 16 | 1Met-ox | 100 | 122 | 1 | SVTELNGDIITNTMTLGDIVFKR |
| 2670.23 | 2670.26 | 13 | 58 | 80 | 1 | VIQNEFTVGEECELETMTGEKVK | |
| 2686.37 | 2686.26 | 40 | 1Met-ox | 58 | 80 | 1 | VIQNEFTVGEECELETMTGEKVK |
| 2970.50 | 2970.49 | 4 | 1Met-ox | 7 | 31 | 1 | YQLQSQENFEAFMKAIGLPEELIQK |
An example of the MS-Fit database ‘in depth’ search results where ‘m/z submitted’ is the experimentally obtained tryptic masses, ‘MH+ matched’ is the theoretical tryptic mass obtained after theoretical digestion of L-FABP, which the experimental tryptic mass has been matched to, ‘delta ppm’ is the difference between the experimentally and theorectically obtained tryptic masses. ‘Modifications’ identifies the modification on any peptide, where 1Met-ox is the oxidation of one methionine residue, and AcetN is the acetylation of the N-terminus. ‘start’ & ‘end’ identifies the position of the tryptic peptide within the protein sequence. ‘Missed cleavages’ identifies how many times trypsin missed a cleavage site. ‘Database sequence’ shows the sequence of the tryptic fragment matched in the database.