Ponsati B, Giralt E, Andreu D
Department of Organic Chemistry, University of Barcelona, Spain.
Anal Biochem. 1989 Sep;181(2):389-95. doi: 10.1016/0003-2697(89)90260-1.
A novel approach to the preparation of immunopeptide-carrier protein conjugates of improved chemical definition based on a solid-phase synthetic protocol combining incorporation of a Cys(Npys) N-terminal residue with systematic acetylation after every coupling, is described. The potential of the method is demonstrated in a synthesis of the tridecapeptide (Npys)-Cys-Val-Asn-Tyr-Ile-Arg-Lys-Arg-Ser-Leu-Gln-Thr-Val-OH in which the main product is purposely contaminated by a number of shorter truncated sequences resulting from intentionally defective couplings. From this peptide crude, and rather independently of its complexity, the target sequence can be selectively recovered and attached to a carrier molecule through a disulfide bond formed by reaction of the Npys-protected cysteine residue and a thiol function in the carrier. The process can be properly named purification-by-conjugation.
