Gradual non-enzymatic deamidation of asparagine or rearrangement of aspartic acid residues during storage or handling can result in isoaspartic acid residues 70–85% of the time.
ISOQUANT® Isoaspartate Detection Kit
This kit uses a sensitive, nonradioactive HPLC method for detecting and quantifying deamidated peptides.
A protocol for quantitative detection of isoaspartic acid residues in proteins and peptides.