Dual Binding Assay Highlights Allosteric Binding Effect on the Bispecific Zenocutuzumab

Author: Stuart Knowling, Ph.D | Last updated: January 2026

Resource overview

Bispecific molecules are designed to bind two targets, but in practice one binding event can modulate the other. This application note shows how Octet® BLI based assay formats enable a more quantitative functional characterization of bispecifics beyond a simple “binds/doesn’t bind” outcome.

Using a HER2 × HER3 bispecific antibody (zenocutuzumab) as an example, we demonstrate a dual binding approach that measures both interactions within a single workflow and compares sequential binding (A→B vs B→A) to reveal binding order effects that conventional endpoint assays may fail to detect. The study also shows how the same format can be adapted to estimate the proportion of correctly-assembled, functionally active dual binding bispecific species in mixed samples during protein engineering and optimization.

 

Resource details

  • Document type: Application note
  • Page count: 10
  • Read time: 23 minutes

 

Key takeaways

  • Dual binding in a single assay workflow: Assess binding to both targets in one Octet® BLI experiment.
  • Binding order and interdependence insight: Compare A→B vs B→A binding sequences to evaluate interdependence and binding order effects.
  • Quantification of functional bispecific content: Estimate changes in the fraction of correctly assembled bispecifics with functional dual binding during optimization.

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