Product Details​

Source: Purified from human red blood cells by fractionation. Exhibits highest activity, soluble and homogenous.

Formulation: Liquid. In 20mM Tris-HCl, pH 7.2, containing 1mM EDTA, 1mM 2-mercaptoethanol, and 50% glycerol.
Buffer ingredients can be adjusted to customer needs.
Shipping: Shipped on Dry Ice
Long Term Storage: -80°C. Avoid freeze/thaw cycles.​​

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Scientific Background​

The 20S proteasome is the catalytic core of the 26S proteasome, the central protease of the ubiquitin pathway of protein degradation. Unlike the 26S proteasome, which degrades proteins in an ATP-dependent manner, the 20S proteasome is ATP-independent and only degrades entirely unfolded polypeptides. 

The 20S proteasome is a conserved degradation machinery that is essential for maintaining cellular homeostasis. The architecture of the 20S proteasome particle is highly conserved, forming a 700-kDa cylindrical structure whose proteolytic active sites are encapsulated within its inner chamber. The 20S proteasome is composed of 28 subunits, arranged in four heptameric rings (α7β7β7α7). In eukaryotes, the two outer rings consist of seven distinct α-subunits each. Similarly, seven different subunits form the two inner β-rings, three of which are responsible for the proteasome’s proteolytic activities. The β1 subunit displays caspase-like activity, β2 shows trypsin-like activity, and the β5 subunit possesses a chymotrypsin-like function. Together, these catalytic subunits ensure the degradation of numerous protein substrates. 

Use/Stability​

The Proteasome 20S purified in our lab without aggregates is ideal for Cryo-EM (Cryogenic electron microscopy), for example, as conducted in the study of Jason E. Gestwicki (Full text).

20S Proteasome remains relatively stable and active so long as repetitive freeze-thaw cycles are avoided. It has been demonstrated that 20S proteasome undergoes only slow loss of activity when stored at 4°C for up to six months. If it is to be used on a regular basis, it is recommended that the material should be stored between 0°C-4°C during the duration of use. For longer-term storage, the material may be dispensed as single-use aliquots and stored at -80°C.​​​​

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Literature References
1) The YΦ motif defines the structure-activity relationships of human 20S proteasome activators, Kwadwo A. Opoku-Nsiah, Jason E. Gestwicki, et al.; Nat Commun.;13(1):1226, (2022), Full Text

 

2) Structural insights into substrate recognition and processing by the 20S proteasome: I. Sahu and Michael H. Glickman; Biomolecules, 11(2), 148, (2021), Full Text

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