The effect of lysine residues on the deamidation reaction of the asparagine side chain has been studied on the peptide and on its lysine-acetylated derivative in a wide range of pH values. The amino acid sequence of these peptides is similar to the local sequence flanking the labile Asn-67 in RNAse A. The experimental data show that Lys influences both the deamidation rate and the relative yield of the two reaction products, i.e., the aspartic acid and beta-aspartic acid containing peptide. These effects are pH dependent and can be rationalized based on the mechanism previously proposed for the deamidation reaction via succinimide derivative.
Copyright 2000 John Wiley & Sons, Inc.