Peptide Conjugation
What is Peptide Conjugation?
Peptide conjugation is a broad approach that encompasses the attachment of chemical moieties to peptides for several reasons including to improve their drug and diagnostic properties. Conjugates used in peptide therapeutics can either be nonbiological molecules like polyethylene glycol (PEG) or biological molecules such as lipids, sugars, nucleic acids, and proteins.
What types of Peptide Conjugations are there?
Protein Conjugation
Protein conjugates come into play in antibody generation. Oftentimes, to elicit a stronger antigenic immune response and generate specific antibodies the target peptides are conjugated to carrier proteins. To prevent antibodies from targeting the carrier proteins and linker regions in vivo, these specific antibodies need to be removed via purification beforehand.
Peptide-protein conjugation often uses thiol-maleimide chemistry, where a cysteine residue is added to the peptide for coupling with a maleimide-modified protein. The conjugates are shipped as chilled solutions for optimal immunization.
An alternative, Multiple Antigenic Peptides (MAPs), consist of multiple peptide branches covalently attached to a lysine backbone. MAPs can induce immune responses without needing a carrier protein. They are commonly available with 4 or 8 branches.
Frequently used carrier protein candidates:
- KLH (keyhole limpet hemocyanin, MW 4.5x105 - 1.3x107 Da) is the most frequently used carrier protein because of its high immunogenicity compared to other proteins. (Note that the solubility of KLH in water is limited. This makes solutions sometimes appear cloudy, though this does not affect immunogenicity. KLH is routinely used for vertebrate research because there are no homologous vertebrate proteins resulting in little if any non-specific antibody activity.)
- BSA (bovine serum albumin, MW 67x103 Da) is a popular carrier protein for weakly antigenic compounds because of the high number of accessible Lys residues for conjugation. Ideally used in invertebrate studies.
- OVA (ovalbumin, MW 45x103) is a protein isolated from chicken eggs. It is often used as a control carrier protein to verify if antibodies produced with KLH/BSA are specific for the target peptide vs. the carrier protein. Ideally used in invertebrate studies.
- HSA (human serum albumin, MW 67 x103 Da).
You can of course consider any other kind of proteins for conjugation.
For more information on protein conjugation, reach out to experienced customer support team, or read up on the topic on our website. Select KLH/BSA Conjugate Peptide synthesis , or consider a separate and more tailored peptide synthesis approach for your conjugation requirement:
KLH/BSA Conjugate Peptide Service Peptide Synthesis
Lipid Conjugation
Membrane-active peptides (MAPs) can be designed to enhance liposomal release by conjugating them to lipid head groups through thiol-maleimide chemistry, making them useful for the delivery and release of pharmaceuticals. These liposomal drug delivery systems typically offer excellent biocompatibility, prolonged circulation times, biodegradability, and the ability to carry both hydrophilic and lipophilic therapeutic agents.
Commonly used of naturally occuring peptide-lipid conjugates are:
Glycosyl-phosphatidyl-inositol (GPI) Anchors: GPI anchors are naturally occurring lipid modifications that tether proteins to cell membranes in many eukaryotic cells. Often used to study membrane localization and protein function, they also come in handy as drug delivery tools.
- Cell-penetrating peptides (CPPs), such as the TAT-peptide, derived from HIV-1 is often conjugated with lipid to facilitate the crossing of lipid-bilayers. We also often a variety of ready-to-use CPPs in our catalog!
- Lipopeptides are used to study the interaction with membranes or create antimicrobial agents
- Ampiphatic peptides also interact with the lipid bilayer and are used to study membrane fusion, vesicle and micelle formation. One such example is melittin , the active component in bee venom which has the potential to disrupt cancer cells.
- Lipid conjugates in vaccine development: conjugation of epitope-covering peptides to lipids may enhance the cell’s immune response
DNA & Oligonucleotide Conjugation
Peptide Oligonucleotide Conjugates have a wide range of applications from drug delivery systems to targeted treatments to target gene expression in medicine. While oligonucleotides have difficulty penetrating the cell membrane and are easily degradable, conjugation can prevent this and facilitate binding and endocytosis via membrane surface receptors, e.g. by conjugation to cell penetrating peptides . Moreover, conjugates have been shown to be tissue specific making them promising candidates for drug delivery and treatment via genetic modulation.
Other Molecules
Want to conjugate drugs or any other molecules with our peptides? Reach out to us, and discuss your ideas! We are here to assist with your questions, and also offer contract research services for larger projects.
Our Comprehensive Peptide Conjugation Service
At JPT, we offer a complete conjugation service designed to meet your specific research needs. Leveraging our extensive experience, we provide:
Peptide Synthesis and Purification: High-quality peptides are synthesized and purified according to stringent standards.
Custom Conjugation Chemistry: We help you select the most suitable conjugation chemistry, whether it’s glutaraldehyde, carbodiimide (WSC), or succinimide esters (e.g., MBS, SMCC), tailored to your peptide’s specific requirements.
Conjugate Selection: Beyond the most common protein conjugates, we offer a variety of other carrier proteins, lipids, oligonucleotides, and other molecules. We assist in choosing the best carrier to ensure optimal antibody production. Talk to us!