2 μg K48-linked tetra-ubiquitin run on 4-12% SDS-PAGE gel under reducing conditions, then visualized with Colloidal Coomassie Blue Stain.

Recombinant K48-linked Tetra-ubiquitin

Ub/Ubl's

Product Code: TUB-057

Verified Applications: Poly-ubiquitin chains exhibit diversity in length, linkage type, and associated cellular functions. K48-linked tetra-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. Note: Exposure of this product to elevated temperatures in SDS-PAGE sample buffer may lead to anomalous high-molecular-weight smearing during electrophoresis, which does not reflect its actual purity. For improved resolution, we recommend pre-incubation in SDS-PAGE buffer at temperatures below 60 °C for 20 minutes prior to gel loading.

Activity: Fully hydrolyzed by the K48-specific OTUB1* deubiquitylase.

Purity: 95%

Concentration: 29 μM

For Research Use Only (RUO)

Protein Name: K48-linked Tetra-ubiquitin

UniProt #: Ub

Predicted Molecular Mass: 34 kDa

Background and Additional Info

Background: Comprised of four 76 amino acid ubiquitin units joined via an isopeptide bond at K48. X-ray structures at neutral pH reveal a rigid, globular arrangement in the closed state (PDB 2O6V) that agree well with NMR structures. K48-linked chains of four or more ubiquitin’s are optimal for high-affinity engagement by proteasome shuttle factors (e.g., hHR23A), and by the p97–Ufd1–Npl4 segregase complex. Many Targeted Protein Degradation approaches depend on K48 poly-ubiquitylation of target proteins.

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).

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Additional Product Information

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 tetra-ubiquitin (Ub₄-K48, K48-tetraUb)

Protein Sequence: MQIFVKTLTGKTITLEVEPSDTIENVKAKIQDKEGIPPDQQRLIFAGKQLEDGRTLSDYNIQKESTLHLVLRLRGG