Activity: Fully hydrolyzed by the K48-specific OTUB1* deubiquitylase
Verified Applications: Poly-ubiquitin chains exhibit diversity in length, linkage type, and associated cellular functions. K48-linked di-ubiquitin serves as a valuable reagent in assays involving ubiquitin-binding proteins and as a substrate for ubiquitin-specific deubiquitylating enzymes (DUBs). Optimal enzyme concentrations should be empirically determined based on the specific assay context.
2 μg UBA1 run on 4-12% SDS-PAGE gel under reducing conditions, then visualized with Colloidal Coomassie Blue Stain.
Formulation: 10 mM HEPES, pH 7.6
Shipping: The product is shipped with dry ice or equivalent. Upon receipt, store it immediately at the temperature recommended below.
Storage and Stability: Use a manual defrost freezer and avoid repeated freeze-thaw cycles. Aliquot and store ≤ -20°C (stable for 48 months from date of receipt).
Protein Sequence: MQIFVKTLTGKTITLEVEPSDTIENVKAKIQDKEGIPPDQQRLIFAGKQLEDGRTLSDYNIQKESTLHLVLRLRGG
Background Information and Alternate Names
Species & architecture
Comprises two 76-aa ubiquitin units joined via an isopeptide bond at Lys48. X-ray structures reveal a rigid, globular arrangement in the closed state (PDB 3M3J), while an alternative open crystal form shows a solvent-exposed interface (PDB 3NS8). NMR and SAXS confirm pH-dependent interconversion between these states.
UPS pathway role
Lys48-linked chains of four or more ubiquitins are optimal for high-affinity engagement by shuttle factors (e.g., hHR23A) and the 26S proteasome, yet di-ubiquitin already binds the proteasomal receptors Rpn10 and Rpn13 with measurable affinity and is recognized synergistically by the p97–Ufd1–Npl4 segregase complex during ER-associated degradation.
References
Ye, Y., et al., (2003) J Cell Biol 162:71-84. PMID 12847084
Eddins, M.J., et al., J Mol Biol 367:204-211 (2007) . PMID 17240395
Trempe, J-F., et al., (2010) Acta Cryst F 66:994-998. PMID PMC2935213
Lai, M-Y., et al., (2012) BBA-Mol Cell Res 1823:2046-2056. PMID 22542781
Grice, G. L., and J. A. Nathan (2016) Cell Mol Life Sci 73:3497-3506. PMID 27137187
Alternate Names: Human Lys48-linked di-ubiquitin (Ub2K48, Ub2-K48), sometimes abbreviated K48-Ub₂
