Chemical Cleavage of Proteins at Asparaginyl-Glycyl Peptide Bonds

Reaction with hydroxylamine has been used to cleave DNA and to deacylate proteins (at neutral pH; see Note 6). At alkaline pH, however, hydroxylamine may be used to cleave the asparaginyl-glycyl bond (see Note 1). This cleavage tends to generate large peptides, as this pairing of relatively common residues is relatively uncommon, representing about 0.25% of amino acid pairs, according to Bornstein and Balian (1). It is therefore generally not useful for identification of proteins by mass mapping, which is better served by larger numbers of peptides. It may be a useful method for further cleavage of large peptides.