Chiral analysis of the reaction stages in the Edman method for sequencing peptides

Abstract

Chiral isothiocyanate reagents suitable for ‘Edman sequencing’ have been synthesised and used to assess the chiral features of individual stages in the Edman method. Using h.p.l.c. analysis of the diastereoisomeric thiohydantions obtained, it has been deduced that the cyclisation and cleavage of thiazolinone step is the likely source of racemisation of the chiral centre derived from the N-terminal amino acid.