Pharmacist Blog about what I encounter and find useful/interesting

The proteasome Proteins are constantly being synthesized and at the same time being degraded in each cell of our body. One of the most known mechanisms of proteolysis (= protein degradation) is the degradation done by lysosomes. However, an other important mechanism is degradation by the ubiquitin proteasome system (UPS). First of all, it is needed to understand that a cell maintains its protein concentration by a constant turn-over of proteins: when there is a lot of synthesis of a certain protein, this certain protein will also be degraded by a higher level, and vice versa. A protein that has to be degraded will be marked by a polyubiquitin chain which consists of 4 or more ubiquitinmolecules. This protein will be transported to a 26S proteasome. This structure in the cell is built by a 19S part and a 20S part. The 19S part mainly serves as a recognition and binding structure for the polyubiquitinated protein, and the 20S part will destroy the protein. Once attached to the