Tandem Ubiquitin Binding Entities (TUBEs) are engineered domains with strong affinity for ubiquitin, offering up to a 1000‑fold increase in binding to polyubiquitin compared to single UBAs. They protect polyubiquitinated proteins from degradation, enabling sensitive detection and efficient capture of proteins in their native polyubiquitinated state. TUBEs isolate, enrich, and identify ubiquitinated proteins from cell and tissue extracts. Magnetic TUBE 2 beads allow efficient recovery without centrifugation, improving removal of unbound material and reducing background. Polyubiquitinated proteins can be easily eluted for proteomic or Western blot analysis. UM502M uses high‑capacity polymeric magnetic beads to enhance enrichment while minimizing nonspecific binding in complex lysates.