mustymod - Eclair for Samsung Galaxy
Would you like to react to this message? Create an account in a few clicks or log in to continue.

Proteasome..

2 posters

Go down

Proteasome.. Empty Proteasome..

Post  taixyz1992 Tue Nov 23, 2010 12:20 am

Proteasomes are very large protein complexes inside all eukaryotes and archaea, and in some bacteria. In eukaryotes, they are located in the nucleus and the cytoplasm.[1] The main function of the proteasome is to degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that carry out such reactions are called proteases. Proteasomes are part of a major mechanism by which cells regulate the concentration of particular proteins and degrade misfolded proteins. The degradation process yields peptides of about seven to eight amino acids long, which can then be further degraded into amino acids and used in synthesizing new proteins.[2] Proteins are tagged for degradation with a small protein called ubiquitin. The tagging reaction is catalyzed by enzymes called ubiquitin ligases. Once a protein is tagged with a single ubiquitin molecule, this is a signal to other ligases to attach additional ubiquitin molecules. The result is a polyubiquitin chain that is bound by the proteasome, allowing it to degrade the tagged protein.[2]

In structure, the proteasome is a large barrel-like complex containing a "core" of four stacked rings around a central pore. Each ring is composed of seven individual proteins. The inner two rings are made of seven β subunits that contain the six protease active sites. These sites are located on the interior surface of the rings, so that the target protein must enter the central pore before it is degraded. The outer two rings each contain seven α subunits whose function is to maintain a "gate" through which proteins enter the barrel. These α subunits are controlled by binding to "cap" structures or regulatory particles that recognize polyubiquitin tags attached to protein substrates and initiate the degradation process. The overall system of ubiquitination and proteasomal degradation is known as the ubiquitin-proteasome system.


Vintage Prom Dresses
climber reviews

taixyz1992

Posts : 12
Join date : 2010-10-17

Back to top Go down

Proteasome.. Empty Re: Proteasome..

Post  heroisthai12 Fri Dec 03, 2010 5:03 am

The inner two rings are made of seven β subunits that contain the six protease active sites



_______________
land rover parts car
baby online registry

heroisthai12

Posts : 199
Join date : 2010-11-21

Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum