Non-stoichiometric inhibition in biochemical high-throughput screening

Introduction: Over the last 2 decades, high-throughput screening (HTS) has become one of the key strategies for the generation of new leads. Non-stoichiometric inhibition is one of the most extensively studied mechanisms responsible for the large percentage of hit compounds from biochemical screens that cannot be developed into leads. Therefore, HTS hit lists need to be sorted rapidly and efficiently into stoichiometrically binding inhibitors and compounds that affect enzyme activity non-stoichiometrically. Areas covered: This article explores the non-stoichiometric inhibition of enzymatic activity in biochemical screens, particularly by compound aggregation, and the authors explain the terminology they use to describe such compound behavior. The paper then provides a short historical overview of both academic and industrial research on compound aggregation specifically. Finally, the article discusses the implications for industrial drug discovery and the measures that can be taken to identify non-stoichiometric and aggregating inhibitors early in this process. Expert opinion: The most pragmatic approach in a lead finding campaign is to focus on the early identification of selective and stoichiometric inhibitors. The combination of multiple approaches (assessing both activity and binding) allows the enrichment of stoichiometric inhibitors at each stage of the flowchart.