Small‐Molecule Screening Made Simple for a Difficult Target with a Signaling Nucleic Acid Aptamer that Reports on Deaminase Activity

Problem child: The application of signaling DNA‐aptamer technology to the development and execution of a high‐throughput screen for an otherwise problematic target, adenosine deaminase (ADA), is reported. The approach employed a signaling DNA aptamer that reports on adenosine concentration (see scheme). The assay was robust in a screen of more than 44 000 molecules and revealed a new competitive inhibitor of the deaminase.