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Bio-Synthesis offers peptide conjugation services using a variety of immunogenic carrier proteins, enzymes, toxins, drugs or oligonucleotides for use as an immunogen or for affinity purification. A variety of immunogenic carrier proteins such as Keyhole Limpet Hemocyanin (KLH), Diphtheria Toxoid has been used in conjugation with several peptide chemistries. We also offer coupling of peptides to various types of gel to create an immunosorbent for positive or negative selection of macromolecular binding entries such as antibodies.
Since target delivery involves the use of a biological vector that is covalently bound to a therapeutic agent such as drugs, biologic, toxins etc, Bio-Synthesis also offers peptide-drug conjugation services. Peptide-drug conjugation consists of a peptide delivery vector, a therapeutic warhead and a linker that covalently attaches the vector and the warhead. These peptide delivery vectors are often short peptides with less than 40 amino acids. For example, cell-penetrating peptides (CPPs) such as Tat CPP peptides derived from the HIV transcriptional activator protein. In our laboratory, this peptide often been use to conjugate to an antisense oligonucleotide. Learn more about peptide-oligonucleotide conjugates.
Peptide conjugation is performed using a variety of methods depending on the amino acid composition and project requirements. The N-terminal amine can be labeled if no internal Lys residues are present in the peptide. The C-terminal acid can be labeled if no Glu and Asp residues are present in the peptide. Artificial amino acids containing a functional group that is orthogonal (non-interfering) to peptide functional groups can be incorporated during the peptide synthesis. Cys can also be added at the N-termini to incorporate a thiol functionality if no Cys residues are present in the peptide.
 Lee, A.C., Powell, J.E., Tregear, G.W., Niall, H.D. and Stevens,
V.C. (1980) A method for preparing b-hCG COOH peptide-carrier conjugates of predictable
composition. Mol. Immunol. 17; 749-756. 10/13