Carrier Protein-Conjugated Peptide Synthesis

Peptides must be conjugated to a carrier protein to induce the formation of antibodies to elicit an immune response. The most common method for conjugating peptides to proteins is based on thiolmaleimide chemistry - a highly specific and robust reaction. CD Formulation offers custom carrier protein conjugated peptide synthesis services. Our scientists have developed a range of chemical crosslinking methods to best meet the specific needs of each customer in project design.

Why Should Peptides be Conjugated to Carrier Proteins?

The endeavor of immunizing with bare peptide antigens often yields disheartening results. These diminutive fragments typically lack the heft to elicit a robust immune reaction autonomously. To navigate this inherent limitation and evoke a powerful antibody response against these peptides, one must intertwine them with a protein carrier such as keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA), or ovalbumin (OVA). This intricate dance of conjugation frequently transpires in solution, subsequently mingling with an adjuvant to amplify the immune response. Alternatively, there exists the tantalizing option of binding the carrier to a solid support, activating it, and engaging in solid-phase chemistry to fuse it with the peptide.

Fig. 1 Immunogen conjugate production by peptide epitope and carrier protein conjugation. (Camperi SA, et al., 2020)

Explore Our Carrier Protein-Conjugated Peptide Synthesis Services

CD Formulation provides complete carrier protein-peptide conjugation services. With our extensive experience, our scientists can handle any challenges that may arise during the carrier protein-peptide synthesis process. Our services include:

Carrier Protein Conjugation Peptide Synthesis Service

Our scientists synthesize high-quality peptides according to strict standards.

Custom Cross-linking Chemistry Options

We assist you in navigating the intricate labyrinth of conjugation chemistry, ensuring you select the most fitting approach tailored to the unique demands of your peptide. This encompasses a kaleidoscope of options, including:

• Glutaraldehyde: Attaches the carrier molecule to the N-terminus of the peptide.
• Carbodiimide (WSC): Attaches the carrier to the C-terminus of the peptide.
• Succinimidyl esters (e.g. MBS, SMCC): Bind to free amino groups and Cys residues.

Carrier Protein Selection

We offer a variety of carrier proteins such as BSA, OVA, etc. for custom peptide conjugates. We assist in selecting the best carrier to ensure optimal antibody production.

Quality Control Testing

We support peptide purification to eliminate low molecular weight contaminants and perform QC/QA using MALDI MS (except KLH).

Choose the Right Carrier Protein for Your Protein-Conjugated Peptide

Carrier Protein	Description
KLH	KLH is the most common carrier protein. It is more immunogenic than other conjugated proteins.
BSA	BSA is the most stable and soluble albumin, containing 59 lysines, of which 30-35 can bind. It is a commonly used carrier protein for weakly antigenic compounds.
OVA	OVA is a protein isolated from chicken eggs. It is often used as a control carrier protein to verify that the antibody is directed against the target peptide and not the carrier protein.

Optional Attachment Sites for Peptides and Carrier Proteins

Depending on the chemical bonding method, our scientists are able to design and synthesize synthetic peptides with specific chemical handles to ensure optimal exposure of the peptide on the surface of the protein carrier. In addition, we introduce rigid or flexible spaces to fine-tune the distance from the carrier surface. Common attachment site options for peptides to carrier proteins include:

• Peptides are attached to the carrier protein through carboxyl groups within the peptide sequence (D, E and C-terminal carboxyl groups).
• Peptides are attached to the carrier protein through amino groups within the peptide sequence (K and N-terminal amino groups).
• Peptides are attached to the carrier protein through the thiol group of a cysteine residue within the peptide sequence.

Choose the Right Conjugation Strategy for Your Protein-Conjugated Peptide

There are two different linker chemistries for carrier protein-conjugated peptides: maleimidyl technology and Hydralink technology.

Maleimidyl Technology

Maleimidyl technology facilitates the formation of classical linkers, where proteins are attached to any free amine group via standard amide bond formation. Peptides are attached to linkers by adding a free thiol to the maleimide functional group to bind to the protein. The peptide-protein bond formed by this technology is chemically stable and can't be broken under standard laboratory conditions.

Hydralink Technology

The technology couples peptides with free aminooxy (RO-NH₂) or hydrazino-nicotinamide (HyNic) groups to any desired carrier protein. In contrast to standard thiol-maleimide chemistry, this Hydralink chemistry leaves the disulfide bonds completely intact, thus avoiding the scrambling of SS bonds under free thiol conditions.

Our Preparation Method for Carrier Protein-Conjugated Peptide

The most commonly used method for preparing carrier protein-conjugated peptides is solution coupling. Solution coupling methods can be divided into:

One Pot-Method

The one-pot method involves adding the cross-linker and peptide to the carrier protein, followed by dialysis to remove unwanted compounds.

Fig. 2 One-pot preparation of carrier protein-conjugated peptides. (CD Formulation)

Two-Step Coupling Method

The two-step coupling method involves forming a covalent bond between the carrier protein and the peptide through two distinct reactions. Initially, the cross-linker is connected to the carrier protein through an amide bond. To eliminate any unreacted coupling agents, techniques such as gel filtration or dialysis are typically employed prior to the coupling of the peptide.

Peptide Manufacturing & Analytical Services

In addition to peptide synthesis capabilities, CD Formulation combines flexible GMP manufacturing facilities with cutting-edge peptide analytical knowledge to provide a full range of quality control testing services to accelerate the commercialization of your products, including:

Publication

CD Formulation is a trusted partner for peptide synthesis. Please don't hesitate to contact us if you are considering using carrier protein-conjugated peptides in your project. We look forward to cooperating with you.

How It Works

STEP 1

Submit a service request describing your specific research or development need.

STEP 2

We'll email you to provide your quote and confirm order details if applicable.

STEP 3

Execute the project with real-time communication, and deliver the final report promptly.