Racemization of an L-phenylalanine residue catalysed by an adjacent cysteine in a bradykinin peptide antagonist

Abstract

A number of peptides and proteins contain aromatic amino acid residues adjacent to a cysteine group in their primary sequence. Analysis of the ratios of D- to L-phenylalanine residues in some bradykinin antagonists has revealed that racemization occurs during conventional strong acid hydrolysis of the parent peptides. The mechanism for this unusual transformation appears to involve intramolecular catalysis by an adjacent cysteine residue.