Target—probe-enzyme

Table 11. Immunoassays Target-Probe-Enzyme Interactions...

Activity-based protein profiling (ABPP) is a chemical proteomic strategy in which active-site-directed covalent probes are used to profile the functional states of enzymes in complex proteomes. Activity-based probes (ABPs) can distinguish active enzymes from their inactive zymogens or inhibitor-bound forms. They contain a reactive group intended to modify enzyme active sites covalently and a reporter group (typically rhodamine or biotin) that assists in detection and identification of protein targets. 

A competitive version of ABPP identifies the target(s) and assesses the selectivity of an enzyme inhibitor in biological systems by gauging how well the inhibitor slows the enzyme s reaction with an ABP. For example, fluorophosphonate ABP 3 was used to profile the selectivity of fatty acid amide hydrolase (FAAH) inhibitors within the serine hydrolase superfamily [27] (FAAH hydrolyzes endocannabinoids such as anandamide). Serine hydrolases that exhibited reduced labeling by the probe in the presence of inhibitor were scored as targets of the inhibitor. Urea FAAH inhibitors exemplified by PF-3845 (5) that covalently modify the active-site serine nucleophile of FAAH were found to be exquisitely selective for FAAH in brain and liver... 

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