Table 1.
Casein Isoforms Identified by using Phosphoprotein Enrichment Combined with Top-Down and Bottom-Up Proteomics
| Protein ID |
Protein | Measured Mr (Da) |
Theoretical Mr (Da) |
MMA (ppm) |
Modifications |
|---|---|---|---|---|---|
| 1 | β-casein, variant B | 24092.2150 | 24092.2661 | −2.12 | 5 phosphorylations, P67H(SNP) and S122R (SNP) to variant A2 |
| 2 | β-casein, variant A1 | 24023.1573 | 24023.1971 | −1.66 | 5 phosphorylations, P67H(SNP) to variant A2 |
| 3 | β-casein, variant A2 | 23983.1426 | 23983.1910 | −2.02 | 5 phosphorylations |
| 4 | β-casein, variant A1 | 23943.1404 | 23943.2290 | −3.70 | 4 phosphorylations, P67H(SNP) to variant A2 |
| 5 | β-casein, variant A2 | 23903.1304 | 23903.2229 | −3.87 | 4 phosphorylations |
| 6 | α-casein2, variant B | 25066.1316 | 25066.0832 | 1.93 | 9 phosphorylations |
| 7 | α-casein2, variant B | 25146.0688 | 25146.0513 | 0.70 | 10 phosphorylations |
| 8 | α-casein2, variant B | 25225.9789 | 25226.0194 | −1.61 | 11 phosphorylations |
| 9 | α-casein2, variant B | 25305.9335 | 25305.9875 | −2.13 | 12 phosphorylations |
| 10 | α-casein2, variant B | 25385.9395 | 25385.9556 | −0.63 | 13 phosphorylations |
| 11 | α-casein2, variant B | 25465.9964 | 25465.9237 | 2.85 | 14 phosphorylations |
| 12 | α-casein1, variant B | 23454.3416 | 23454.3163 | 1.08 | 6 phosphorylations |
| 13 | α-casein1, variant B | 23534.3109 | 23534.2826 | 1.20 | 7 phosphorylations |
| 14 | α-casein1, variant B | 23614.2199 | 23614.2489 | −1.23 | 8 phosphorylations |
| 15 | α-casein1, variant B | 23694.1793 | 23694.2152 | −1.52 | 9 phosphorylations |
| 16 | α-casein1, variant C | 23622.2894 | 23622.1941 | 4.03 | 9 phosphorylations |
| 17 | α-casein1, variant C | 23542.3093 | 23542.2377 | 3.04 | 8 phosphorylations |
| 18 | α-casein1, variant C | 23462.3269 | 23462.2615 | 2.79 | 7 phosphorylations |