INTRODUCTION OF THE MALEIMIDE FUNCTION ONTO RESIN-BOUND PEPTIDES - A SIMPLE, HIGH-YIELD PROCESS USEFUL FOR DISCRIMINATING AMONG SEVERAL LYSINES

Incorporation of epsilon-Adpoc-lysine as a residue in solid phase pept ide synthesis allows selective deprotection of this residue on the res in-bound peptide relative to other acid labile groups such as Boc. Pre mature resin cleavage is avoided. A maleimide group, a useful thiol-ca pture reagent, was readily introduced by reacting the liberated amino function with an acylating agent containing the maleimide functionalit y. Acidic cleavage from the resin, with an appropriate scavenging syst em, afforded peptides that are derivatized with a maleimide functional ity on a specific lysine. This is advantageous for producing peptide-c arrier conjugates of defined specificity, useful as immunogens, by mal eimide-thiol coupling. The derivatization and resin removal chemistrie s appear to proceed in excellent yield with respect to the maleimide g roup. The structures were confirmed by tandem mass spectrometry.