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PathHunter® Protein:Protein Interaction Assay Platform


DiscoverX has exploited the versatile features of enzyme fragment complementation (EFC) technology to study specific in vitro interaction between proteins. PathHunter assays employ the widely adapted β-galactosidase complementation system.  In this system, the protein of interest is fused to a small peptide, termed ProLink, that weakly binds a complementary fragment, EA that encodes the rest of the β-galactosidase enzyme.  The ProLink peptide is 42 aa in length and lacks significant secondary structure, making it an ideal fusion partner.  The other protein of interest is fused at its C-terminus to the EA enzyme fragment.  Interaction between the  two tagged proteins result in forced complementation of the enzyme.  The resulting enzymatic activity is detected in a single addition, mix-and-read format. The magnitude of the measured enzyme activity correlates with the amount of ProLink tagged protein-protein EA complex formed. The chemiluminescent signal is compatible with standard laboratory luminescence detection equipment and can be employed directly, with no data manipulations or processing.

PathHunter Protein:Protein Assay Principle

Enabling Drug Discovery Across Multiple Target Classes







Features & Benefits

  • Measure protein interactions in intact mammalian cells
  • Chemiluminescent, gain-of-signal assays – no antibodies, radioactivity or imaging
  • Standard instrumentation – no complex data analysis, normalization or pit/vesicle spot detection required
  • Full length protein – ideal for large molecule therapeutics and small molecule inhibitors
  • High specificity – tagged protein eliminates background from endogenous proteins
  • High quality reproducible data – superior assay windows & robust performance (Z' > 0.6)

Explore Target Biology With Multiple Technology Platforms

GPCR β-Arrestin Assay Platform

PathHunter β-Arrestin GPCR assays are whole cell, functional assays that directly measure GPCR activity by detecting the interaction of β-Arrestin with the activated GPCR.

Learn more about GPCR B-arrestin Assays >

Kinase Cell Based Assay Platform

PathHunter kinase assays offer a large panel of cell-based assay solutions for functional activity, characterization and screening. This portfolio uses full length protein to provide a cellular context to the kinase activation and is well-suited for identifying novel inhibitors and therapeutic antibodies.

Learn more about Kinase Cell Based Assays >

Nuclear Hormone Receptor Assay Platform

PathHunter protein interaction assay detects binding of an agonist or antagonist to the ligand binding domain of the nuclear hormone receptor (NHR) of interest and the triggering of a functional response.   

Learn more about NHR Assays >