This kit is designed for enrichment of cellular proteins conjugated with linear polyubiquitin chains using GST-NEMO (UBAN). Polyubiquitinated proteins bound on GST-NEMO (UBAN) can be precipitated using glutathione resin and eluted by a buffer containing 10 mM glutathione. Polyubiquitinated proteins can be assayed by immunoblotting or mass spectrometry.