Identification and quantification of the unpaired cysteine residues in the C1-CK fragment
| Peptide . | Free cysteine residue . | Abundance in sample . | Ratio of carboxyamidomethyl to methyldisulfide . | |
|---|---|---|---|---|
| Carboxyamidomethyl . | Methyldisulfide . | |||
| GCDVCTCTDME | 2453 | 521 147 | 173 452 | 3.00 |
| VAQCSQKPCEDSCR | 2468/2473 | 36 701 | 284 780 | 0.13 |
| TSACCPSCR | 2574 | 161 978 | 656 725 | 0.25 |
| TVMIDVCTTCR | 2600 | 43 408 | 180 645 | 0.24 |
| EENNTGECCGR | 2640 | 95 707 | 561 872 | 0.17 |
| IPGTCCDTCEEPE | 2715/2716 | 194 631 | 914 022 | 0.21 |
| Peptide . | Free cysteine residue . | Abundance in sample . | Ratio of carboxyamidomethyl to methyldisulfide . | |
|---|---|---|---|---|
| Carboxyamidomethyl . | Methyldisulfide . | |||
| GCDVCTCTDME | 2453 | 521 147 | 173 452 | 3.00 |
| VAQCSQKPCEDSCR | 2468/2473 | 36 701 | 284 780 | 0.13 |
| TSACCPSCR | 2574 | 161 978 | 656 725 | 0.25 |
| TVMIDVCTTCR | 2600 | 43 408 | 180 645 | 0.24 |
| EENNTGECCGR | 2640 | 95 707 | 561 872 | 0.17 |
| IPGTCCDTCEEPE | 2715/2716 | 194 631 | 914 022 | 0.21 |
The ratio of carboxyamidomethyl (free cysteines) to methyldisulfide (paired cysteines) labeling represents the fraction of the cysteine (underlined) in the population that is in the reduced state. Peptides with ratios > 0.1 are listed. The remaining cysteine containing peptides detected by mass spectrometry have ratios < 0.1 and are listed in supplemental Table 1.