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APT280 20S Proteasome Activity Assay

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      Key Specifications Table

      Species ReactivityKey Applications
      Ma ACT
      Catalogue NumberAPT280
      Brand Family Chemicon®
      Trade Name
      • Chemicon
      Description20S Proteasome Activity Assay

      The ubiquitin-proteasome pathway is the major proteolytic system in the cytosol of eukaryotic cells, where it catalyzes the selective degradation of short-lived regulatory proteins and the rapid elimination of proteins with abnormal conformation (Hershko & Ciechanover 1998; Hochstrasser 1996). The critical protease in this pathway is the 26S proteasome, an ATP-dependent proteolytic complex, which is formed by the association of the barrel-shaped 20S proteasome (700-kDa) and two 19S (700-kDa) regulatory complexes (Baumeister et al. 1998; Coux et al. 1996). The 20S Proteasome, catalytic core of the proteasome complex, is responsible for the breakdown of key proteins involved with apoptosis, DNA repair, endocytosis, and cell cycle control (Coux et al. 1996; Hoffman & Rechsteiner 1996; Hochstrasser 1995). The CHEMICON Proteasome Activity Assay Kit provides a quick, efficient and sensitive system for evaluation of proteasome activity in cell lysates or inhibitor screening.

      Test Principle:

      Chemicon's Proteasome Activity Assay Kit provides a simple and convenient means for assaying proteasome activity that recognize the substrate LLVY (Meng et al. 1999). The assay is based on detection of the fluorophore 7-Amino-4-methylcoumarin (AMC) after cleavage from the labeled substrate LLVY-AMC. Absorption=351nm. Emission=430nm. The free AMC fluorescence can be quantified using a 380/460 nm filter set in a fluorometer.

      A proteasome inhibitor, Lactacystin, is included as a test inhibitor for screening purpose. Lactacystin is a microbial natural product and the most specific and potent inhibitor of proteasomes currently known (Fenteany & Schreiber 1998).


      The Proteasome Activity Assay Kit is a relatively quick method for detection of intracellular proteasome activity. Testing of purified proteasome enzyme, in vitro inhibitor screening and the study of proteasome regulation can be performed with this assay.

      The CHEMICON Proteasome Activity Assay Kit is intended for research use only, not for diagnostic or therapeutic applications.
      Materials Required but Not Delivered· 96-well fluorometer plate

      · Adjustable volume pipettor with disposable tips

      · 37°C incubator

      · DMSO

      · Fluorometer with a 380/460nm filter set
      Product Information
      • 20S Proteasome Positive Control (Part No. 90205): One vial containing 20S Proteasome Positive Control in 20 mM Tris, pH 7.2 and 1 mM DTT.
      • 10X Assay Buffer (Part No. 90209): One 1.5 mL vial.
      • Proteasome Substrate (Suc-LLVY-AMC) (Part No. 90206): One vial contains 500 μg peptide substrate.
      • Lactacystin (20S Proteasome Inhibitor) (Part No. 90208): One vial contains 9.4 μg inhibitor.
      • AMC Standard (Part No. 90207): One vial contains 2.2 μg AMC standard.
      Quality LevelMQ100
      ApplicationThe Proteasome Activity Assay Kit provides a simple & convenient means for assaying proteasome activity that recognize the substrate LLVY.
      Key Applications
      • Activity Assay
      Application NotesLysis buffer: 50 mM HEPES (pH 7.5), 5 mM EDTA, 150 mM NaCl and 1% Triton X-100. Addition of 2 mM ATP to the lysate will improve the recovery of intact 26S proteasome.

      Also see: Hoffman, L. 1992 at for additional methods for isolation.

      Preparation of the proteasome sample can be done by many different methods. This paper in JBC is a good reference,, however the method unfortunately requires 100,000g spins and DEAE columns but it does provide very, very clean and active proteasomes,

      An easier yet more crude preparation is typically done for most studies.

      The cell lysis buffer is, 50 mM HEPES (pH 7.5), 5 mM EDTA, 150 mM NaCl and 1% Triton X-100. Addition of 2 mM ATP to the lysate will improve the recovery of intact 26S proteasome. The addition of ATP is optional.

      Cell Extraction
      Note: This protocol has been successfully applied to several cell lines.
      Users should optimize the cell extraction procedure for their own applications.

      1. Collect cells in PBS by centrifugation (non-adherent cells) or scraping from culture flasks (adherent cells).

      2. Wash cells twice with cold PBS.

      3. Remove and discard the supernatant and collect the cell pellet. At this point the cell pellet can be frozen at -80°C and lysed at a later date.

      4. Lyse the cell pellet in 0.5 mL lysis buffer for 30 minutes, on ice, with vortexing at 10-minute intervals.

      *To get a rough idea you could adjust the cell concentration to around 2 x 107 cells/mL. Resulting protein concentration of the cell lysate should be 2-4 mg/mL using this lysis buffer.
      **The volume of cell lysis buffer depends on the cell line, the cell number in cell pellet and the amount of poly-ubiquitinated protein. For example, 1 x 107 MCF-7 cells can be extracted in 0.5 mL of cell lysis buffer.

      5. Transfer the lysate to microcentrifuge tubes and centrifuge at 15,000 rpm for 15 minutes at 4°C.

      6. Aliquot the clear extract to clean microcentrifuge tubes. These cell lysates are ready for assay.
      The cell lysate can be stored at -80°C. Avoid multiple freeze/thaw cycles. After thaw the cell lysate, Centrifuge at 15,000 rpm for 15 minutes at 4°C again since the cell lysate should be clear of any sediments or particulate matter.

      Isolation of 20S core: Additional info: The crude protocol will provide 20S material, not exclusively but the 20S will be present as it is the core of the 26S particle .

      Lliterature references abound for isolation of 20S proteasome from various tissues including for example, skeletal muscle. The isolation is done essentially the same way as the crude method but the spins are much higher, with the final spin being 100,000 x g for six hours, after which the pellet is resuspended and pooled. A good general reference is the following, Hayter JR et al, 2005, Mol. Cell Proteomics, PMID:15965267

      "Purification of the 20S proteasome: The purification protocol was based upon previously published methods, adapted for purification of the complex from large or smaller quantities of tissue [see reference]. Chick skeletal muscle was mechanically homogenised using a domestic food processor in 1.5 volumes of buffer A (20mM Tris, 20mM KCl, 10mM magnesium acetate, 2mM DTT, 10% glycerol pH 7.6). The soluble protein fraction was isolated by centrifugation at 30,000g for 30min at 4°C.

      The pellet was discarded and the supernatant fraction was centrifuged again at 100,000g for 6h. The supernatant fraction was again discarded and the pellet was washed carefully in fresh buffer, which was also discarded. The washed pellets were resuspended in 1ml of buffer A (per pellet), pooled and stored at -20°C in 1.5ml aliquots.
      Biological Information
      Species Reactivity
      • Mammals
      Entrez Gene Number
      Entrez Gene SummaryThe proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. The core structure is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. This gene encodes a member of the peptidase T1A family, that is a 20S core alpha subunit. A pseudogene has been identified on the Y chromosome.
      Gene Symbol
      • PSMA1
      • MGC22853
      • MGC14751
      • PROS30
      • MGC1667
      • HC2
      • MGC21459
      • PSC2
      • MGC14542
      • PROS-30
      • MGC23915
      • NU
      • MGC14575
      • EC
      UniProt Number
      UniProt SummaryFUNCTION: SwissProt: P60900 # The proteasome is a multicatalytic proteinase complex which is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. The proteasome has an ATP-dependent proteolytic activity.
      SIZE: 246 amino acids; 27399 Da
      SUBUNIT: The proteasome is composed of at least 15 non identical subunits which form a highly ordered ring-shaped structure.
      SUBCELLULAR LOCATION: Cytoplasm. Nucleus.
      SIMILARITY: SwissProt: P60900 ## Belongs to the peptidase T1A family.
      Physicochemical Information
      Materials Information
      Toxicological Information
      Safety Information according to GHS
      Safety Information
      Product Usage Statements
      Usage Statement
      • Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.
      Storage and Shipping Information
      Storage ConditionsStore kit materials (as provided) at -20°C up to their expiration date.
      Packaging Information
      Material Size1 kit
      Transport Information
      Supplemental Information


      20S Proteasome Activity Assay SDS


      Safety Data Sheet (SDS) 


      Reference overviewPub Med ID
      When cytokinin, a plant hormone, meets the adenosine A2A receptor: a novel neuroprotectant and lead for treating neurodegenerative disorders?
      Lee, YC; Yang, YC; Huang, CL; Kuo, TY; Lin, JH; Yang, DM; Huang, NK
      PloS one  7  e38865  2012

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      Proteasome inhibition with bortezomib depletes plasma cells and autoantibodies in experimental autoimmune myasthenia gravis.
      Alejandro M Gomez,Kathleen Vrolix,Pilar Martínez-Martínez,Peter C Molenaar,Marko Phernambucq,Eline van der Esch,Hans Duimel,Fons Verheyen,Reinhard E Voll,Rudolf A Manz,Marc H De Baets,Mario Losen
      Journal of immunology (Baltimore, Md. : 1950)  186  2011

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      C terminus of Hsc70-interacting protein (CHIP)- mediated degradation of hippocampal estrogen receptor-alpha and the critical period hypothesis of estrogen neuroprotection.
      Zhang QG, Han D, Wang RM, Dong Y, Yang F, Vadlamudi RK, Brann DW
      Proceedings of the National Academy of Sciences of the United States of America  108  E617-24. Epub 2011 Aug 1.  2011

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      Inhibition of autophagy in the heart induces age-related cardiomyopathy.
      Manabu Taneike,Osamu Yamaguchi,Atsuko Nakai,Shungo Hikoso,Toshihiro Takeda,Isamu Mizote,Takafumi Oka,Takahito Tamai,Jota Oyabu,Tomokazu Murakawa,Kazuhiko Nishida,Takahiko Shimizu,Masatsugu Hori,Issei Komuro,Takuji Shirasawa Takuji Shirasawa,Noboru Mizushima,Kinya Otsu
      Autophagy  6  2010

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      An HDAC1-binding domain within FATS bridges p21 turnover to radiation-induced tumorigenesis.
      Z Li,Q Zhang,J-H Mao,A Weise,K Mrasek,X Fan,X Zhang,T Liehr,K H Lu,A Balmain,W-W Cai
      Oncogene  29  2010

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      Modulating the hypoxia-inducible factor signaling pathway as a therapeutic modality to regulate retinal angiogenesis.
      M DeNiro,O Alsmadi,F Al-Mohanna
      Experimental eye research  89  2009

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      The proteasome inhibitor bortezomib aggravates renal ischemia-reperfusion injury.
      Huber, Julia M, et al.
      Am. J. Physiol. Renal Physiol., 297: F451-60 (2009)  297  F451  2009

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      Bcl-2 family proteins contribute to apoptotic resistance in lung cancer multicellular spheroids.
      Yang, TM; Barbone, D; Fennell, DA; Broaddus, VC
      American journal of respiratory cell and molecular biology  41  14-23  2009

      Show Abstract Full Text Article
      19097992 19097992
      Curcumin suppresses AP1 transcription factor-dependent differentiation and activates apoptosis in human epidermal keratinocytes.
      Sivaprakasam Balasubramanian, Richard L Eckert
      The Journal of biological chemistry  282  6707-15  2007

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      17148446 17148446
      Lithium leads to an increased FRQ protein stability and to a partial loss of temperature compensation in the Neurospora circadian clock.
      Jolma, Ingunn W, et al.
      J. Biol. Rhythms, 21: 327-34 (2006)  2006

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