Peptide–Carrier Protein Conjugation Services

KLH, BSA, and OVA conjugation for immunogen preparation and assay development.

Peptide–KLH conjugation Peptide–CRM197 conjugation MAP immunogens Blue carrier protein Peptide–BSA conjugates Peptide–OVA conjugation Program-aligned QC

Overview

Peptide–carrier protein conjugation is a specialized form of peptide–protein conjugation in which a synthetic peptide epitope is covalently linked to an immunogenic carrier protein (commonly KLH, BSA, or OVA). These conjugates are used as immunogens for antibody generation and as antigen reagents for screening and assay development.

Bio-Synthesis provides custom peptide–carrier protein conjugation services with controlled attachment strategies selected for your peptide design and intended downstream workflow (immunization vs screening/assay use). We can help plan attachment orientation, handle placement, and practical loading targets, followed by purification and documentation aligned to your program stage.

Schematic: peptide linked to carrier protein (KLH/BSA/OVA) via spacer/linker
Schematic overview: peptide epitope + controlled attachment chemistry + carrier protein.

Related services: Peptide Modifications, Click Chemistry Peptides, Protein & Enzyme Conjugation.

Peptide immunogen vs peptide antigen conjugates — how to choose

Most antibody programs use two related conjugates: an immunogen to raise antibodies and a separate screening/assay antigen to confirm binding is peptide-specific (not carrier-specific).

Immunogen conjugates

Goal: strong immune response to a short peptide epitope.

  • Common carriers: KLH, CRM197, Blue Carrier Protein
  • Carrier-free option: MAP (multiple antigenic peptide)
  • When used: immunization for polyclonal/monoclonal workflows
Antigen / screening conjugates

Goal: clean assay signal with lower anti-carrier background risk.

  • Common carriers: BSA and/or OVA
  • Best practice: screen on a different carrier than the immunogen
  • When used: ELISA screening, assay development, confirmation

Practical tip: a frequent pairing is KLH–peptide for immunization and BSA–peptide or OVA–peptide for screening, which helps reduce false positives driven by anti-carrier antibodies.

Carrier options for peptide immunogen and antigen conjugates

Carrier selection is driven by your goal (immunization vs screening/assay antigen), peptide properties, and the need to minimize anti-carrier background in downstream assays. A common best practice is to immunize with one carrier (e.g., KLH) and screen with a different carrier (e.g., BSA or OVA).

Carrier / option What it is Typical use Notes for planning
MAP (Multiple Antigenic Peptide) A synthetic, branched peptide scaffold (commonly Lys-core) that presents multiple copies of an epitope without a protein carrier. Immunogen Anti-peptide antibody generation when you want to avoid a protein carrier. Eliminates carrier-conjugation as a step; reduces anti-carrier antibodies. Best when epitope tolerates multivalent presentation.
KLH (Keyhole Limpet Hemocyanin) A very large mollusk hemocyanin protein widely used as an immunogenic carrier. Immunogen Primary choice for raising antibodies to short peptide epitopes. High immunogenicity; often paired with BSA/OVA conjugates for screening to reduce anti-KLH background.
CRM197 A non-toxic diphtheria toxin variant used as a carrier in many conjugate-vaccine contexts. Immunogen Programs preferring a well-characterized carrier with vaccine precedent. Useful when carrier choice is informed by translational precedent; conjugation chemistry is selected to preserve protein integrity.
Blue Carrier Protein A large carrier protein preparation that includes a blue chromophore, supporting visual tracking during handling and conjugation. Immunogen Alternative to KLH for certain workflows; also useful in method development. Practical for process visibility; selection depends on assay context and desired carrier pairing strategy.
BSA (Bovine Serum Albumin) A stable, well-characterized serum albumin commonly used in assays. Assay antigen ELISA coating antigen, screening conjugate, method controls. Because BSA is often used as a blocking reagent, consider OVA (or another carrier) for confirmatory assays to reduce background risk.
OVA (Ovalbumin) Egg-white protein frequently used as a secondary carrier for screening/confirmation. Assay antigen Secondary carrier to confirm peptide-specific binding. Often used to confirm antibodies target the peptide rather than the immunization carrier (e.g., KLH or BSA).

If you’re unsure which carrier is best, send your peptide sequence, intended host species, and assay format—we’ll recommend a practical pairing strategy (immunization vs screening) and an attachment approach.

Why peptide–carrier conjugates are used

Antibody generation workflows
  • Peptide immunogens for polyclonal/monoclonal programs
  • Epitope-focused antibodies (including PTM-epitopes)
  • Neutralizing and blocking antibody discovery support
Screening & assay development
  • ELISA coating antigens (BSA/OVA conjugates)
  • Specificity confirmation across carriers
  • Assay controls for method development
Epitope mapping & validation
  • Epitope mapping reagent sets
  • Affinity reagent screening panels
  • Assay-grade conjugates for validation
How conjugation supports immunogenic presentation

Short peptides can be weakly immunogenic on their own. Coupling to a carrier protein (or presenting multiple epitope copies on a MAP scaffold) increases effective size and context, which supports immune recognition while keeping a defined peptide epitope sequence.

Conjugation chemistry options

Thiol-selective (Cys-directed)

A common choice when the peptide includes a single terminal cysteine for oriented coupling.

  • Maleimide–thiol coupling
  • Defined orientation (N- or C- terminal Cys)
  • Good analytical interpretability
Amine / carboxyl coupling

Used when peptides lack thiols or when broad coupling is acceptable for immunogens.

  • EDC/NHS-style amide bond formation
  • Practical for many peptide haptens
  • Loading control via condition tuning
Click-ready handles

Chemoselective coupling when you want clean attachment with defined handles.

  • Azide–DBCO / azide–BCN (copper-free)
  • Defined stoichiometry
  • Useful for assay antigens
Mechanism note (CMC-safe)

Carrier proteins increase the effective size and immunogenic context of short peptides to support antibody generation workflows. Conjugation chemistry is chosen to balance peptide presentation, loading, solubility, and reproducible characterization. See also: click-ready handles and peptide modifications for handle planning.

Design inputs (what we need to quote and plan)

Peptide inputs
  • Peptide sequence + desired epitope orientation
  • Preferred attachment site (N-terminus, C-terminus, internal handle)
  • Handle preference (terminal Cys, Lys, azide/alkyne, etc.)
  • Solubility constraints (hydrophobicity, charge)
Conjugate inputs
  • Carrier protein choice (KLH vs BSA vs OVA)
  • Intended use: immunization vs screening/assay
  • Target scale / concentration and buffer constraints
  • Preferred characterization package (program-aligned)

For immunogens, adding a terminal cysteine (if not present) is a common approach to control attachment orientation; final choice depends on epitope placement and assay goals.

Typical workflow

Process overview
  1. Design review
    – epitope, orientation, handle placement, carrier selection, and intended use.
  2. Peptide synthesis
    – prepare peptide with a defined attachment handle (or agreed coupling plan).
  3. Carrier activation / conditioning
    – prepare carrier protein for selected chemistry.
  4. Conjugation & purification
    – controlled coupling and removal of unconjugated components.
  5. Analytical verification
    – profile checks and documentation aligned to program stage.
Typical workflow for peptide–carrier protein conjugation
Typical workflow for peptide–carrier protein conjugate synthesis, purification, and analytical control.

QC & typical deliverables

For broader bioconjugation needs, see protein & enzyme conjugation and peptide modification options.

Peptide identity
  • Peptide MS confirmation prior to conjugation
  • Purity verification (method-appropriate)
Conjugate profiling
  • Conjugation profile review (method-dependent)
  • Purification options (fit-for-purpose)
  • Buffer exchange as required
Documentation
  • COA aligned to intended use
  • Traceable documentation package (program-dependent)
  • Handling/shipping notes as needed

Peptide loading (substitution) and conjugate profile are chemistry- and carrier-dependent. We align a practical, fit-for-purpose characterization plan to your intended use (immunization vs screening), which may include conjugate profiling methods and documentation appropriate to your program stage.

Our Quality Commitment

Bio-Synthesis is committed to Total Quality Management (TQM) to assure customer satisfaction. Analytical checks are performed following peptide synthesis and conjugation, and purification/QA procedures support high-quality peptide–carrier protein conjugates.

Our quality system follows ISO 9001–aligned practices, with release criteria and documentation scaled to the intended use and program stage.

FAQ

What’s the difference between KLH and BSA/OVA conjugates?

KLH is often selected for immunization due to strong immunogenicity, while BSA/OVA conjugates are commonly used as screening and assay antigens (e.g., ELISA coating controls) and for validation workflows.

Should I add a terminal cysteine to my peptide?

Often, yes—adding a single terminal cysteine can support oriented thiol-selective coupling. Whether to add Cys depends on the epitope location and whether you need N- or C-terminal presentation.

Can you provide different carrier conjugates from the same peptide?

Yes. It is common to prepare KLH conjugates for immunization and BSA/OVA conjugates for screening and assay formats from the same peptide design.

What do you need to generate a quote?

Please provide the peptide sequence, preferred attachment site/handle (or constraints), the carrier protein (KLH/BSA/OVA), intended use (immunization vs assay), quantity, and any buffer/handling requirements.

Contact & quote request

For the fastest quote, send the peptide sequence, desired attachment site/handle (or “recommend”), carrier protein (KLH/BSA/OVA), target quantity, and intended use (immunization vs screening/assay).

Fastest path
Quote checklist
  • Peptide sequence + any required modifications
  • Preferred attachment site/handle (terminal Cys / click / other)
  • Carrier protein (KLH, BSA, OVA)
  • Intended use (immunogen vs screening antigen)
  • Quantity / concentration and buffer constraints

Not sure which route fits your design? Send the epitope region and constraints—we’ll recommend a practical conjugation plan.

Recommended reading

Selected references describing carrier protein conjugation chemistry, site-selective bioconjugation strategies, and assay contexts. Links are provided for scientific context.

  1. Hermanson, G. T. Bioconjugate Techniques, 3rd ed. Academic Press, 2013. Standard reference for protein conjugation chemistry, including carrier protein coupling approaches.
  2. Spicer, C. D.; Davis, B. G. Selectively modified proteins: methods and applications. Nature Communications 2014, 5, 4740. DOI: 10.1038/ncomms5740
  3. Koniev, O.; Wagner, A. Developments and recent advancements in the field of endogenous amino acid selective bond forming reactions for bioconjugation. Chemical Society Reviews 2015, 44, 5495–5551. DOI: 10.1039/C5CS00051A
  4. Thermo Fisher Scientific. Carrier Protein Activation and Conjugation Data for Immunogen Preparation. Link
  5. MilliporeSigma Technical Bulletin. Maleimide Activated KLH. PDF
  6. Example of BSA–peptide conjugates used as immunogens: International Immunology 2024. Link

Note: Publications often describe conjugation chemistry and assay formats without naming synthesis vendors; references are provided for scientific background and method context.

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