Figure 5.

Illustration of the mechanisms of protein labeling and subsequent analysis using alkynyl-PI(3,4,5)P3 activity probes 2 and 3. Following the incubation of the probes with cell extracts, protein−probe binding events were captured through irradiation of the benzophenone tag. Next, labeled proteins were selectively derivatized via click chemistry using the secondary functional tag of the probe to introduce rhodamine (11) for in-gel fluorescence analysis or biotin (12) for protein enrichment via affinity chromatography and subsequent protein identification using liquid chromatography-tandem mass spectrometry.