Automated C-Terminal Sequencing of Peptides and Proteins

Abstract

The development of a chemical method for the sequential degradation of a protein or peptide from the carboxy-terminus is a goal of our laboratory. Such a method, in addition to complementing existing N-terminal methods of degradation, would be invaluable for the sequence analysis of proteins with naturally occurring N-terminal blocking groups and for the detection of post-translational processing at the carboxy-terminus of expressed gene products. Although several methods for a sequential C-terminal degradation have been proposed (Ward, 1986; Rangarajan, 1988), the thiocyanate method based on the procedure originally published by Schlack and Kumpf (1926) has been the most widely studied. Recent work in our laboratory, introducing new reagents for the derivatization of the C-terminal amino acid (Hawke et al., 1987) and for the specific cleavage of the derivatized amino acid (Bailey and Shively, 1991; Bailey et al., 1992), has suggested that an automated chemical method for the sequential degradation of polypeptides from the carboxy-terminus, analogous to the Edman method for amino terminal degradation, may be feasible.