Epitope mapping identifies the specific amino acid sequence or structural region of a protein that an antibody binds. This information helps you understand how an antibody works. It also confirms that two antibodies in a combination study bind different sites. This supports regulatory documentation for therapeutic antibodies, and it helps you design blocking or non-blocking reagents.
Antibody & Protein Arrays
Peptide Arrays for Epitope Mapping and Antibody Characterisation
Peptide mapping arrays for precise antibody epitope identification and characterisation
Peptide mapping arrays screen hundreds of overlapping peptides at the same time, in a single hybridisation. This builds a positional binding profile across a target protein.
The arrays print synthesised peptides that tile across the target protein sequence onto glass slides. You incubate your antibody sample on the array. A fluorescent secondary antibody then detects where the antibody has bound. This gives you a positional binding map across the peptide set.
PD-L1 epitope mapping arrays are available for three antibody species: human IgG, mouse IgG, and rabbit IgG. Each array covers the PD-L1 sequence with overlapping peptides. This lets you pinpoint the antibody binding region precisely, useful for antibody validation, biosimilar characterisation, and epitope binning studies.
Peptide arrays also support protein-protein interaction mapping. You scan a peptide panel from one binding partner against its counterpart protein. This helps you find minimal binding regions or check for competitive interaction sites. Custom tiling arrays are available on request for targets outside the standard catalogue.
Peptide Arrays Compared With Other Characterisation Methods
- If you need to pinpoint which amino acids your antibody contacts on a target protein, a peptide tiling array localises the binding region to within a few residues in a single experiment. This is faster than X-ray crystallography or HDX-MS for linear epitopes, though these structural methods remain necessary for conformational epitopes.
- If you are validating a therapeutic antibody and need to document its epitope for regulatory or biosimilar purposes: glass-based peptide arrays give you reproducible binding profiles you can use as supporting data.
- If you are working on PD-L1 antibody characterisation: ready-to-order panels for human, mouse, and rabbit IgG cover this target, so you do not need custom synthesis.
- If you need a custom peptide tiling array for a target that is not in the existing panel: custom tiling arrays are available on request.
- If you only need to confirm antibody specificity rather than map its epitope: a western blot or ELISA against the full-length protein is simpler. A peptide array works best when you need positional epitope information.
Applications
Therapeutic antibody development
Peptide mapping confirms two candidate antibodies bind non-overlapping epitopes before combination studies, supporting epitope binning decisions.
Biosimilar development
Arrays document epitope equivalence between the originator and biosimilar antibodies, giving reproducible binding profiles for regulatory submissions.
Autoimmune disease research
Tiling arrays map epitopes recognised by patient autoantibodies, complementing autoantibody profiling arrays to find key regions in rheumatoid arthritis.
Checkpoint inhibitor research
Pre-designed PD-L1 tiling arrays let you map the epitope of new anti-PD-L1 antibodies quickly, without custom peptide synthesis.
Protein-protein interaction mapping
Scanning a peptide panel from one binding partner against recombinant proteins finds minimal binding regions or competitive sites.
Antibody validation and specificity confirmation
Epitope mapping confirms that primary antibodies bind the expected region, supporting routine specificity QC.
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Peptide Mapping Arrays
Peptide Mapping Arrays for Precise Antibody Epitope Identification and Characterisation
Frequently asked questions
A peptide tiling array uses overlapping short peptides, usually 12 to 15 amino acids long. The step size between peptides is one to three residues. Together, these peptides cover the full sequence of the target protein. They are printed on a glass slide or membrane.
You incubate the array with an antibody of interest. This reveals which peptides bind, and pinpoints the linear epitope at single-residue resolution.
A linear epitope is a continuous stretch of amino acids that an antibody recognises in the primary sequence. A conformational epitope depends on the folded three-dimensional structure of the protein. It forms from residues that may sit far apart in the sequence but close together in space.
Peptide tiling arrays map linear epitopes only. To map a conformational epitope, use structural techniques such as hydrogen-deuterium exchange mass spectrometry or cryo-electron microscopy.
The resolution depends on the step size between consecutive peptides. A step size of one or two residues narrows the epitope to a two to three amino acid window. It does this by identifying the shortest peptide that still binds and the first peptide in each direction that loses binding.
Larger step sizes of five to ten residues need fewer peptides, but they define the epitope over a broader region.
Parent category: Protein arrays
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