Protein fingerprinting results obtained from the mass spectrometric analysis of tryptic peptides and protein alignment using ProFound
| Gel Section | Incub. | Protein Identified | Peptides Aligned | Coverage | Probability | MS/MS Peptides |
|---|---|---|---|---|---|---|
| h | % | |||||
| ∼55-kDa band | 0 | CYP3A2 | 16 | 33 | 0.62 | |
| CYP3A1/23 | 16 | 39 | 0.38 | |||
| μS Epoxide | ||||||
| 2 | Hydrolase | 10 | 29 | 1.0 | ||
| HMM Bands | 0 | none | ||||
| 2 | CYP3A1/23 | 13 | 43 | 0.99 | 5 | |
| CYP3A2 | 10 | 34 | 0.000004 | 3 | ||
| Ubiquitin (8 kDa) | 0 | Ubiquitin | 7 | 67 | 1.0 |
The ∼55 kDa band and the HMM bands were determined in samples without added ubiquitin. The ubiquitin band was analyzed in a separate sample that contained 100 μM ubiquitin. Probability values for multiple hits on the same or very closely related gene product were summed. For example, in the case of the ∼55-kDa band, ProFound identified two separate entries for CYP3A2 and assigned each a probability of 0.31. The last column identifies the number of peptides for which sequence information was obtained by MS/MS analysis that confirmed that the peptide was from the indicated CYP3A protein. CYP3A1 and CYP3A23 are 98.6% identical. As such, we were typically unable to distinguish peptides from these two proteins using this analysis.