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Blocking peptides – restore trust in your primaries

You want to be certain your primary antibody is binding what it’s supposed to. And only what it’s supposed to! Blocking peptides give you that confidence – that trust – in your primaries.

A simple control with blocking peptides, alongside your western blot or immunostaining protocol, will help to confirm your primary’s specificity. That means less time spent troubleshooting your assay.

  • Available for every polyclonal antibody we offer
  • Peptide confirmation by amino acid analysis and mass spectrometry
  • Quality control of each and every lot by western blot
  • Supplied as a convenient and stable lyophilized powder

What are blocking peptides?

Blocking peptides are a valuable control in Western blotting and immunostaining (IHC, ICC/IF) techniques. They comprise the original peptide antigen used in immunization, against which an antibody was raised. Consequently, they are sometimes referred to as immunizing peptides. We have previously referred to them at Alomone Labs as ‘negative control antigens’. Blocking peptides can be used to compete or block antibody binding, and are therefore a valuable control to determine antibody specificity in Western blotting (WB) and immunostaining experiments.

When are they used?

The inclusion of a blocking peptide as an experimental control is recommended, to help validate antibody specificity.

Principle for peptide blocking experiments

  • Before you begin a staining protocol using WB, IHC, ICC/IFC techniques, one antibody sample is incubated with an excess of the blocking peptide.
  • The antibody’s ability to recognize the target antigen in your blot, histological sample or cell, is neutralized or ‘blocked’ due to the competitive binding of the immunizing peptide in its place.
  • Comparison with a parallel sample containing the antibody alone can help determine which staining (or band) is specific.
  • The staining or band absent from the sample incubated with the blocking peptide, and present when the antibody is used alone is specific to your target protein.

Alomone Labs is unique in that we have blocking peptides for every single polyclonal antibody we provide.
Furthermore, our blocking peptides undergo rigorous lot-specific QC using Western blotting. 
All blocking peptides are provided in a lyophilized form.

More information and specific online and printable protocols for your technique are available below: