Table 3. Peptides identified with liquid chromatography coupled with high resolution mass spectrometry.
| Papain, fraction 30–10 kDa | ||||||||
| Peptide | -10lgP | Mass (Da) | Length | m/z | RT | Intensity | Accession | PTM |
| SEEQQQTEDELQDKIHPFA | 82.14 | 2271.0291 | 19 | 1136.524 | 25.3 | 9.41E+07 | β-casein | |
| DKFLDDDLTDDIM(+15.99) | 81.56 | 1570.6708 | 13 | 786.3439 | 28.5 | 1.52E+08 | α-lactalbumin | Oxidation (M) |
| Q(-17.03)TEDELQDKIHPFAQ | 77.76 | 1780.8268 | 15 | 891.421 | 26.4 | 3.34E+07 | β-casein | Pyro-glu (from Q) |
| DKFLDDDLTDDIMC(+119.00) | 76.84 | 1776.6892 | 14 | 889.353 | 30.8 | 8.22E+07 | α-lactalbumin | Cysteinylation |
| K(+114.04)FLDDDLTDDIM | 76.45 | 1553.6919 | 12 | 777.8535 | 31.5 | 2.58E+07 | α-lactalbumin | Ubiquitin |
| TEDELQDKIHPFA | 75.67 | 1541.7361 | 13 | 771.8761 | 24 | 1.51E+08 | β-casein | |
| KTVDMES(+79.97)TEVFTK | 74.74 | 1593.6997 | 13 | 797.8574 | 21.6 | 1.48E+07 | αS2-casein | Phosphorylation (STY) |
| DKFLDDDLTDDIMC(+305.07)V | 74.32 | 2061.8218 | 15 | 1031.928 | 33.9 | 2.49E+08 | α-lactalbumin | Glutathione disulfide |
| DKFLDDDLTDDIMC(+133.02)V | 72.64 | 1889.7733 | 15 | 945.8951 | 31.5 | 1.40E+07 | α-lactalbumin | S-homocysteinylation |
| EEQQQTEDELQDKIHPFA | 70.57 | 2183.9971 | 18 | 1093.007 | 24.9 | 6.98E+06 | β-casein | |
| DKFLDDDLTDDIMC(+267.03)VK | 70.4 | 2151.8799 | 16 | 1076.944 | 35.1 | 1.26E+08 | α-lactalbumin | Nitroso Sulfamethoxazole Sulfinamide thiol adduct |
| DKFLDDDLTDDIMC(+119.00)VK | 70.1 | 2003.8525 | 16 | 1002.935 | 28.9 | 3.03E+07 | α-lactalbumin | Cysteinylation |
| KFQS(+79.97)EEQQQTEDELQDKIHPF | 70.05 | 2683.1802 | 21 | 895.4025 | 26.7 | 6.06E+07 | β-casein | Phosphorylation (STY) |
| Papain, fraction <5 kDa | ||||||||
| Peptide | -10lgP | Mass (Da) | Length | m/z | RT | Intensity | Accession | PTM |
| DKFLDDDLTDDIM(+15.99) | 85.45 | 1570.6708 | 13 | 786.3438 | 28.4 | 6.11E+07 | α-lactalbumin | Oxidation (M) |
| Q(-17.03)QQTEDELQDKIHPFA | 72.32 | 1908.8854 | 16 | 955.4519 | 27.1 | 1.32E+07 | β-casein | Pyro-glu (from Q) |
| DKFLDDDLTDDIM | 71.94 | 1554.6759 | 13 | 778.3455 | 31.9 | 2.61E+07 | α-lactalbumin | |
| YPFPGPIHN(+.98)SLPQ | 68.73 | 1466.7194 | 13 | 734.3683 | 28.5 | 5.21E+07 | β-casein | Deamidation (NQ) |
| Q(-17.03)TEDELQDKIHPFAQ | 66.45 | 1780.8268 | 15 | 891.4222 | 26.4 | 1.55E+07 | β-casein | Pyro-glu (from Q) |
| DKFLDDDLTDDIMC(+305.07)V | 65.91 | 2061.8218 | 15 | 1031.928 | 33.9 | 4.42E+07 | α-lactalbumin | Glutathione disulfide |
| DELQDKIHPFA | 63.65 | 1311.6459 | 11 | 656.8309 | 24.1 | 6.43E+08 | β-casein | |
| Q(-17.03)TEDELQDKIHPF | 63.5 | 1581.7311 | 13 | 791.8743 | 27.4 | 2.86E+07 | β-casein | Pyro-glu (from Q) |
| DK(+14.02)FLDDDLTDDIM | 62.12 | 1568.6915 | 13 | 785.3544 | 31.9 | 6.95E+06 | α-lactalbumin | Methylation(KR) |
| KFLDDDLTDDIM(+15.99) | 61.63 | 1455.6439 | 12 | 728.8304 | 27.9 | 2.25E+07 | α-lactalbumin | Oxidation (M) |
| Q(-17.03)TEDELQDKIHPFA | 60.21 | 1652.7682 | 14 | 827.3926 | 27.2 | 1.40E+08 | β-casein | Pyro-glu (from Q) |
| DKFLDDDLTDDIMC(-2.95)V | 59.88 | 1753.808 | 15 | 877.9135 | 29.4 | 4.20E+06 | α-lactalbumin | Carbamidomethylated Cys that undergoes beta-elimination and Michael addition of methylamine |
| KPEDETHLE | 59.86 | 1096.5037 | 9 | 549.2592 | 12.9 | 1.61E+08 | GLYCAM1 | |
-10lgP is a score indicating the quality of the identification, m/z is the mass to charge ratio of the fragmented ion, PTM, Post Translational Modification, indicates the type of modification and amino acid (in brackets) on which the modification occurs.