| 摘要 |
The present invention provides a method of quantifying the activity of a protein modifying enzyme in a sample, comprising: (i) grouping modified peptides from a first sample and modified peptides from a second sample into a single group according to one of the following parameters: (a) modified peptides having a modification site that is modified by the same protein modifying enzyme; or (b) modified peptides having a modification site that is part of the same modification motif; (ii) calculating enrichment of the modified peptides from the first sample compared to the modified peptides from the second sample in the group; and (iii) calculating the statistical significance of said enrichment; wherein a statistically significant enrichment is indicative of a protein modifying enzyme being activated in the first sample compared to the second sample. In some embodiments, the method further comprises identifying modified peptides in a first sample and a second sample using mass spectrometry (MS) prior to step (i). |
