800.227.0627

Conjugation method?

In order to generate immune response, peptides should be conjugated to bigger carrier proteins. You have a choice of BSA, ovalbumin, or KLH. One of the advantages of KLH (keyhole limpet hemocyanin) is that it does not interfere with ELISA or Western Blot because it is not used for blocking reagent. General conjugation method is maleimide method which couples the Cysteine residue of the peptide to the carrier protein. For the peptide conjugation, one Cysteine residue should be added to N- or C-terminus of the peptide in order to be linked to carrier protein. Please select a less important terminus to be conjugated to protein. If your peptide is N-terminal sequence of a protein, addition of Cysteine to C-terminus will be good, and vice versa. If your peptide has internal Cysteine residue, C-terminal conjugation via the carboxyl group by EDC method is used when there is no Glu, Asp residues, or N-terminal conjugation via amino group by Glutaraldehyde method is used when there is no Lys residue. One can also use Amine-to-amine crosslinkers with polyethylene glycol (PEG) spacer arms. BS(PEG)5 and BS(PEG)9 are bis-succinimide ester-activated PEG compounds for crosslinking between primary amines (–NH2) in proteins and other molecules. This type of cross linking is advisable to use with hydrophobic peptide because it provides several advantages as:

  • Irreversibly crosslink proteins or peptides by flexible PEG spacer arms
  • Polyethylene glycol spacer arms help maintain conjugate solubility
  • Pure compound with defined structure and molecular weight, ensuring reproducible protein-modification effects
  • PEG spacer provides unique advantages, including increased stability, reduced tendency toward aggregation and reduced immunogenicity