Tandem Ubiquitin Binding Entities (TUBEs) are engineered proteins with strong affinity for ubiquitin, showing up to a 1000‑fold increase in binding to polyubiquitin chains compared to single UBAs. They protect polyubiquitinated proteins from degradation, enabling sensitive detection and efficient isolation of native ubiquitinated proteins from cell and tissue extracts. TUBEs “capture” proteins in their polyubiquitinated state, making them valuable for enrichment and identification studies. Magnetic TUBE 1 beads allow rapid, single‑step recovery of polyubiquitinated proteins without centrifugation, improving removal of unbound material and reducing background. Proteins can be easily eluted for downstream Western blot or proteomic analysis. UM501M uses high‑capacity polymeric magnetic beads to enhance enrichment while minimizing nonspecific binding.