The ubiquitin system

Trends Biochem Sci. 1997 Oct;22(10):383-7. doi: 10.1016/s0968-0004(97)01122-5.


Eukaryotes contain a highly conserved multi-enzyme system that covalently links ubiquitin to a variety of intracellular proteins that bear degradation signals recognized by this system. The resulting ubiquitin-protein conjugates are degraded by the 26S proteasome, a large ATP-dependent protease. Pathways that involve ubiquitin underlie a multitude of processes, including cell differentiation, the cell cycle and responses to stress.

MeSH terms

  • Cysteine Endopeptidases / chemistry
  • Multienzyme Complexes / chemistry
  • Proteasome Endopeptidase Complex
  • Proteins / chemistry*
  • Ubiquitins / chemistry*


  • Multienzyme Complexes
  • Proteins
  • Ubiquitins
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex