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. Author manuscript; available in PMC: 2017 Jan 28.
Published in final edited form as: J Am Chem Soc. 2016 Dec 5;138(49):15841–15844. doi: 10.1021/jacs.6b10589

Figure 1.

Figure 1

A kinetic selectivity model for covalent small molecules and its application to Ibrutinib. A, Standard covalent inhibitor (CI). Fast on-target (green arrow) and slower off-target reactivity (red arrow). Kinetically-selective CI. Fast on-target (green arrow) and slower off-target reactivity (red arrow), with an intermediary rate of hydrolysis of the electrophilic fumarate ester to unreactive free acid (orange arrow). B, Ibrutinib-based compounds and probes. C, 2 is hydrolyzed to inactive 5 by hCES1-, but not hCES2- or control protein (MetAP2)-transfected HEK293T cells. Cells were treated with 2 (10 μM, 1 h) prior to extraction and LC-MS analysis to quantify relative amounts of 2 and 5.