Characterization of Small Molecule to Protein Binding

Label-free technologies are mostly used for detection of biomolecular interactions between proteins or other macromolecules. Characterization of small molecule to protein binding has often been a challenge because label-free signal depends on molecular weight of the analyte and analyte-to-target molecular weight ratio. In this study we show that Nanopore Optical Interferometry (NPOI) can be used for accurate measurement of an enzyme interaction with inhibitors as small as 95 Da. We provide statistical analysis of data fidelity and correlate our results with published data obtained by Surface Plasmon Resonance (SPR). In addition, we show that the same enzyme binding surface can be used multiple times in automated runs for screening and characterization of multiple analytes.