Screening system for D-Asp-containing proteins using D-aspartyl endopeptidase and two-dimensional gel electrophoresis

D-Asp-containing proteins have been implicated in many aging-related diseases. To clarify the role of D-Asp-containing proteins in such diseases, we developed a screening system for these proteins using a D-aspartyl endopeptidase that specifically cleaves the proteins at the C-terminus. The digested proteins were detected by means of two-dimensional gel electrophoresis and identified using nano-liquid chromatography/tandem mass spectrometry. We were able to detect myelin basic protein, a known D-Asp-containing protein, in the brain tissues of mice; this indicates that our system is effective for screening D-Asp-containing proteins.