Protein degradation via ubiquitination is a major proteolytic mechanism in cells. Once a protein is destined for degradation. it is tagged by multiple ubiquitin molecules. The synthesised polyubiquitin chains can be recognised by the 26S proteosome where proteins are degraded. https://www.lecoureures.shop/product-category/course-a-pied-homme-vetements-pantalon-track/