In addition to our standard peptide synthesis service, we offer several peptide modifications for a variety of applications. According to individual needs, we can produce C-amidated, N-acetylated, biotin labelled, fluorescein-labelled, phosphorylated, cyclic, and D-amino acid containing peptides, as well as MAPs.
Linear peptides can also be bound to a solid support like sepharose for affinity purification of antigen specific polyclonal antibodies (see antibody purification section). Sepharose-peptide affinity columns canalso be used to study interactions between immobilized peptide and its ligand or between antisense peptide and the immobilized sense peptide.
For enhanced immunogenicity we are able to provide you with two modification options:
a. Conjugation
Synthetic peptides are normally small molecules, which are not able to elicit a significant immune response. However, when they are coupled to a larger carrier molecule, the immune system will then respond to the hapten-carrier complex producing antibodies against the peptide and the carrier protein. We offer you the choice between the most commonly used carrier-proteins: BSA, KLH, OVA and others upon request. There is a variety of reagents used for peptide to the carrier linkage:
- Glutaraldehyde, which cross-links primary NH2-groups on the peptide to those of the protein
- Sulfo-SMCC (Sulfosuccinimidil 4-N-maleimidomethyl-cyclohexane-1-carboxylate), a heterobifunctional reagent that binds, in a two-step reaction, the primary amines of the carrier protein and the sulphydryl group of the cysteine of the peptide. For peptide sequences lacking cysteine residues, we suggest the addition of a cysteine either at the N- or C-terminus of the peptide depending on several criteria
b. Maps
An alternative system to produce antibodies using peptide-conjugates is to use MAPs (Multiple Antigenic Peptides). In this case, the peptide chain grows on a 4 branching lysine core. Lysine has two amino groups and can be used to build up a large branching lysine complex.
In general, we recommend to use the 4-branch MAP resin for peptides containing more than 15 amino acid residues and the 8 branch MAP resin for peptides shorter than 15 amino acids. The desired epitope should be at the distal flexible end of the peptide. This approach produces a higher titer of anti-peptide antibodies, eliminating the presence of contaminant anti-carrier antibodies.