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A proteasome is a developed protease, notably involved in the degradation and eradication of proteins deemed by the cell to be unnecessary, thus being essential in ensuring that all proteins maintain a high quality. Moreover, proteasomes control cell-cycle progression and apoptosis which act as a crucial target in anti-cancer therapy[1].

As stated in the paper of Peters, et al., 1994: 'Proteasomes are very large protein complexes found in some of the living organisms'[2]. and differ from normal proteases owing to compartmentalisation and isolation of certain cell features. They constitute 'nearly 1% of cell protein' and are completely reliant on ATP. When a protein is incompletely folded (usually owing to a lack of aid from a molecular chaperone), it is then marked by a 'protein rescue' mechanism which is able to recognise it's 'abnormally exposed hydrophobic patch' allowing it to then be destroyed by the proteasome[3]. This mechanism usually involves 'ubiquitination and proteasomal degradation and therefore is known as the ubiquitin-proteasome system'[4].


  1. The proteasome: structure, function, and role in the cell. 2003 May;29 Suppl 1:3-9
  2. Peters, Jan-Michael; Franke, Werner W.; Kleinschmidt, Jiirgen A. (March 1994). "Distinct 19 S and 20 S subcomplexes of the 26 S proteasome and their distribution in the nucleus and the cytoplasm". The Journal of Biological Chemistry 269 (10): 7709–18. PMID 8125997
  3. Albert B, Johnson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P., 'Molecular Biology of the Cell'. 6th Ed, Abingdon: Garland Science, Taylor and; Francis Group, LLC, 2015.
  4. Nassif, Nicholas D., Cambray, Samantha E., Kraut, Daniel A.,'Slipping up: Partial substrate degradation by ATP-dependent proteases'IUBMB Life 66(5): 309–317, 2014

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