| Mass Spectrometry-based Enzyme Assays for Rapid Inhibitor Screening |
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Presentation: P03042 Session: Robotic Screening & Automation Technologies - Poster SessionS. Zhou, G. Davis, E. Dolan, T. Burt, A. Evdokimov, V. Easwaran, J. Roesgen, R. Kawamoto, A. Carr, and K. Greis, Procter & Gamble Pharmaceuticals Presenting Author: Kenneth Greis, Procter & Gamble Pharmaceuticals - USA Mass Spectrometry (MS) has been widely reported for measuring the conversion of substrates to products for enzyme assays. Matrix-assisted laser desorption ionization, time-of-flight MS (MALDI-TOF MS) offers a direct readout of substrate and product, a fast sampling rate, and is tolerant of many buffer salts, reagents and compound that are typically found in enzyme reaction mixtures. Unfortunately, the reproducibility and quantitative capabilities of MALDI have always been questionable. New interest in MALDI-TOF MS for quantitative measurements have emerged with the development of matrix additives to suppress matrix clusters coupled with rapid data acquisition rates to allow for better signal averaging and reproducibility. In this report, the general utility of MALDI-TOF MS for enzyme assays and compound screening is demonstrated. Absolute quantitation is demonstrated to be unnecessary since relative ratios of substrates and products, as measured by MALDI-TOF MS, provide sufficient relative quantitation and reproducibility to rank order compound for potency. |