An electrophoretic approach to screen for glutamine deamidation.

Protein deamidation is a posttranslational modification with important implications in physiology and medicine. There is, however, no simple technique for a rapid screening of protein deamidation. The deamidating activity of transglutaminase was applied to establish a simple method for the screen of protein deamidation using recombinant human growth hormone, a rat hippocampal membrane fraction, and a cell homogenate enriched in 5-hydroxytryptamine-1A receptor as model systems. Here we report a simple, economic, and fast approach to assess protein deamidation by two electrophoretic methods: differential cleavage on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) via in situ V8 protease digestion and the principle of spot shifting via blue native (BN)-PAGE/two-dimensional (2D)-SDS-PAGE/immunoblotting.