<prompt> Ubiquitin is a key molecule in protein degeneration. Ubiquitinated proteins are degraded byChaperoneProteaseProteasomeCaspase  <response>: Ubiquinated proteins are degraded by Proteasomes. Abnormal proteins and aged normal proteins conjugate to the polypeptide ubiquitin and then it marks them for degradationUbiquitination. The Ubiquitinated proteins are degraded by Proteasomes. Proteasome inhibitor, Boezomib, is used in multiple myeloma and hepatocellular carcinoma Ref: Harpers illustrated Biochemistry 31st edition Pgno: 664, 1434 