It basically churns and breaks down that protein into smaller peptides while the 19s subunits basically bind to the poly ubiquitinated protein and they protect other proteins from actually entering the core and being broken down. So if we look at the steps that involve this process, we can summarize the steps in this diagram. So let's suppose we have some protein shown here. And this protein has been ubiquitated with these ubiquitous molecules. So we have five here, we have five here and we have five here. So now that we marked this protein for degradation, the 19th as subunits not shown here for simplification purposes, these basically locate and bind to this polyubiquid protein.