Analysis of Arginylated Peptides by Subtractive Edman Degradation

During the early studies of N-terminal arginylation, Edman degradation was widely used to identify N-terminally added Arg on protein substrates. This old method is reliable but highly depends on the purity and abundance of samples and can become misleading unless a highly purified, highly arginylated protein can be obtained. Here we report a mass spectrometry-based method that utilizes Edman degradation chemistry to identify arginylation in more complex and less abundant protein samples. This method can also apply to the analysis of other posttranslational modifications.