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Cytoplasmic organelle, composed of a cylindric core particle bound by two regulatory particles at each end, responsible for degrading endogenous proteins. Proteins to be destroyed are recognized by proteasomes because of the presence of ubiquitin conjugated to the targeted protein's lysine residue.
See also: ubiquitin-protease pathway.
[protease + -some ]


A cellular protein complex consisting of proteolytic enzymes that degrade endogenous proteins, especially those that are damaged, pathogenic, or no longer of use.


, proteosome (prō′tē-ă-sōm″)
An enzymatic (protease) cell organelle that degrades misfolded or damaged proteins and modulates the quantity of regulatory proteins in the cell. The breakdown of proteins by proteasomes (proteolysis) is triggered when damaged proteins are tagged by ubiquitin.


A large, cylindrical protein complex of several sub-units, present in the cytoplasm and nucleus of all cells and an essential component in cell metabolism. The function of the proteasome is to act as a kind of shredder, degrading unwanted proteins that have been tagged for destruction with UBIQUITIN chains. It strips proteins of their ubiquitin, unfolds them and catalyzed them to peptides. Proteasomes have aroused much interest as therapeutic trargets in cancer. The proteasome 26S is involved both in the induction and repression of APOPTOSIS. See also POLYUBIQUITINATION.
References in periodicals archive ?
We are excited to offer patients the first oral proteasome inhibitor as an alternative treatment option for those with multiple myeloma," said Gary Kadlec, president of Diplomat.
The proteasome activity increases considerably during the initial steps of embryonic stem cell differentiation in mice.
mass (kDa)/pl 3217 Proteasome activator complex subunit 3 P61289 29.
Effects of chronic ethanol administration on rat liver proteasome activities: Relationship with oxidative stress.
In the field of cosmetology, a lot of research has been carried out on proteasomes, while the autophagy process remained understudied.
VELCADE is the first proteasome inhibitor to receive worldwide regulatory approval for the treatment of multiple myeloma (MM).
Crude proteasomes were extracted from pressurized (0.
2) used ELISA to measured the concentrations of circulating proteasomes in sera from patients with hematologic malignancies and with various liver diseases and found that they were substantially higher than circulating proteasome in plasma of healthy patients.
A cell marks proteins with this "kiss of death" molecule--itself a small protein--and then shuttles the doomed proteins to its waste-disposal units, called proteasomes.
This volume of Progress in Molecular Biology and Translational Science discusses cutting-edge research of proteasomes and proteasome-associated proteins and cellular systems.
However, variable types of 20S complexes can associate with different regulatory particles, generating functionally distinct proteasomes such as the immunoproteasome (Glickman and Ciechanover 2002; Kloetzel 2004).
Higher-level organisms, such as humans or yeast, also have gate-closed proteasomes to degrade unwanted proteins.

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