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Specificity and competition

Investigate specificity and competitive behavior of your binder

Confirming the specificity of a detected binding is crucial. Compare positive and negative cell lines within the same measurement or pre-incubate with a non-labeled ligand to confirm self-competition. Investigate if two molecules bind to the same epitope by keeping one non-labeled and follow competition (shared epitope) or label with a quencher* and follow binding in proximity (different epitopes).

*Only in LigandTracer Green

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By disrupting an interaction with a non-labeled competitor you not only get insight about shared epitopes, but you can also extract information on the kinetics and affinity of both ligands.

Gained information

  • Cell line specificity – absence of ligand on cells lacking target receptors
  • Target specificity – the possibility to self-compete
  • Epitope mapping – competition between molecules
  • Epitope mapping – quenching of molecules in close proximity



Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941.
Vraka C, Pichler V, Pfaff S, Balber T, Hacker M, Mitterhauser M, Wadsak W, Philippe C.
J. Vis. Exp. 2019. 146

A novel real-time proximity assay for characterizing multiple receptor interactions on living cells.
Bondza S, Björkelund H, Nestor M, Andersson K, Buijs J.
Anal Chem. 2017. 89(24):13212-13218