ETH Zurich, and Swiss Institute of Bioinformatics 1 article published in JoVE Chemistry An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions Mohameedyaseen Syedbasha1, Janina Linnik1,2,3, Deanna Santer4, Daire O'Shea5, Khaled Barakat4,6, Michael Joyce4, Nina Khanna7, D. Lorne Tyrrell4, Michael Houghton4, Adrian Egli1,8 1Applied Microbiology Research, Department of Biomedicine, University of Basel, 2Department of Biosystems Science and Engineering, ETH Zurich, and Swiss Institute of Bioinformatics, 3Swiss Institute of Bioinformatics, 4Li Ka Shing Institute for Virology, University of Alberta, 5Regional Infectious Diseases Unit, University of Edinburgh, 6Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 7Infection Biology, Department of Biomedicine, University of Basel, 8Clinical Microbiology, University Hospital Basel The presented protocols describe two enzyme-linked immunosorbent assay (ELISA) based techniques for the rapid investigation of ligand-receptor interactions: The first assay allows the determination of dissociation constant between ligand and receptor. The second assay enables a rapid screening of blocking peptides for ligand-receptor interactions.