High throughput screening via mass spectrometry: a case study using acetylcholinesterase.

Mass spectrometry-based screening can be applied to a wide range of targets, including those intractable targets that use substrates such as lipids, fatty acids, phospholipids, steroids, prostaglandins, and other compounds not generally amenable to conventional screening techniques. The major limitation to this approach is throughput, making HTS via mass spectrometry impractical. We present a mass spectrometry-based technique and hardware for lead discovery applications. Mass spectrometry enables the design of label-free assays using biologically native substrates for a wide range of enzymatic targets. This system can be used for the direct quantification of analytes in complex reaction mixtures with typical throughputs of 4-5 s per sample. A mass spectrometry-based assay was developed to identify inhibitors of acetylcholinesterase, an enzyme with clinical importance in Alzheimer's disease. The system was used to screen a small chemical library. Several potent inhibitors were identified, and the IC(50) values of the inhibitors were determined.