Abstract

Mass spectrometry (MS) has emerged as a powerful label-free readout to analyze biochemical reactions. Despite an improvement in throughput with newer instrumentation, requirements for sample preparation remain. For example, critical components such as buffers, salts, and detergents lead to ion suppression, limiting the application of MS for drug discovery. Here we describe the combination of high-density biochip arrays presenting self-assembled monolayers (SAMs) of alkanethiolates on gold with matrix assisted laser desorption ionization (MALDI) MS—a technique termed SAMDI—that offers key solutions for drug discovery. The use of SAMs enables the use any buffer component, including salts and detergents, while generating quantitative results at ultra high-throughput speeds for unprecedented data quality. This poster showcases the power of SAMDI for drug discovery by focusing on regulators of phosphorylation. We first demonstrate rapid biochemical assay development for kinase and phosphatase enzymes suitable for characterizing potent inhibitors. Next, we demonstrate affinity selection SAMDI assays to reveal non-covalent small molecule binders. Finally, we highlight the first label-free and high-throughput cell-based assay that reports on specific enzyme activities to identify modulators of cellular phosphatase activities. Taken together, these data demonstrate how SAMDI accelerates drug discovery through assay development, hit identification, and lead optimization from proteins to cells.