Rapid Solid-Phase Construction of Serine Hydrolase Probes Results in Selective Activity-Based Probes for Acyl Protein Thioesterases-1/2.

Serine hydrolases (SHs) are a large, diverse family of enzymes that play various biomedically important roles. Their study has been substantially advanced by activity-based protein profiling, which makes use of covalent chemical probes for labeling the active site and detection by various methodologies. However, highly selective probes for individual SHs are scarce because probe synthesis usually takes place by time-consuming solution phase chemistry. We here report a general solid-phase synthesis toward SH chemical probes, which will speed up probe library synthesis. It involves the construction of a recognition element ending in a secondary amine followed by capping with different electrophiles. We illustrate the power of this approach by the discovery of selective chemical probes for the depalmitoylating enzymes APT-1/2. Overall, this study reports new methodologies to synthesize SH probes, while providing new reagents to study protein depalmitoylation.