Rapid Determination of the Specificity Constant of Irreversible Inhibitors (kinact/KI) by Means of an Endpoint Competition Assay |
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| Authors: | Ikuo Miyahisa Dr. Tomoya Sameshima Dr. Mark S. Hixon |
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| Affiliation: | 1. Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Ltd., 26‐1, Muraoka‐higashi 2‐chome, Fujisawa, Kanagawa 251‐8555 (Japan);2. Modeling & Simulation, Global DMPK, Takeda California, Inc., 10410 Science Center Drive, San Diego, CA 92121 (USA) |
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| Abstract: | Owing to their covalent target occupancy, irreversible inhibitors require low exposures and offer long duration, and their use thus represents a powerful strategy for achieving pharmacological efficacy. Importantly, the potency metric of irreversible inhibitors is kinact/KI not IC50. A simple approach to measuring kinact/KI was developed that makes use of an irreversible probe for competitive assays run to completion against test compounds. In this system, the kinact/KI value of the test compound is equal to (kinact/KI)probe×[probe]/IC50. The advantages of this method include simplicity, high throughput, and application to all target classes, and it only requires an in‐depth kinetic evaluation of the probe. |
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| Keywords: | covalent inhibitors drug discovery irreversible inhibition enzyme kinetics |
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