Global profiling of protease cleavage sites by chemoselective labeling of protein N-termini Academic Article uri icon


MeSH Major

  • Aminopeptidases
  • Aspartic Acid Endopeptidases
  • Proteomics


  • Proteolysis has major roles in diverse biologic processes and regulates the activity, localization, and intracellular levels of proteins. Linking signaling pathways and physiologic processes to specific proteolytic processing events is a major challenge in signal transduction research. Here, we describe N-CLAP (N-terminalomics by chemical labeling of the alpha-amine of proteins), a general approach for profiling protein N-termini and identifying protein cleavage sites during cellular signaling. In N-CLAP, simple and readily available reagents are used to selectively affinity label the alpha-amine that characterizes the protein N terminus over the more highly abundant epsilon-amine on lysine residues. Protein cleavage sites are deduced by identifying the corresponding N-CLAP peptides, which are derived from the N-termini of proteins, including the N-termini of the newly formed polypeptide products of proteolytic cleavage. Through selective affinity purification and tandem mass spectrometry analysis of 278 N-CLAP peptides, we characterized proteolytic cleavage events associated with methionine aminopeptidases and signal peptide peptidases, as well as proteins that are proteolytically cleaved after cisplatin-induced apoptosis. Many of the protein cleavage sites that are elicited during apoptotic signaling are consistent with caspase-dependent cleavage. These data demonstrate the utility of N-CLAP for proteomic profiling of protein cleavage sites that are generated during cellular signaling.

publication date

  • November 17, 2009



  • Academic Article



  • eng

PubMed Central ID

  • PMC2780798

Digital Object Identifier (DOI)

  • 10.1073/pnas.0908958106

PubMed ID

  • 19892738

Additional Document Info

start page

  • 19310

end page

  • 5


  • 106


  • 46