Basis of differentiation | Lysosomes | Proteasomes |
Definition | A lysosome is a membrane-bound organelle that contains digestive enzymes | Proteasomes are protein complexes which degrade unneeded or damaged proteins by proteolysis |
Substrate degradation | Lysosomes degrade cytoplasmic components, including individual proteins, defective or surplus organelles through autophagy, or protein aggregates | Proteasomes degrade individual cellular proteins in a highly targeted manner through the ubiquitin-proteasome system |
Structure | They are spherical vesicles with a single lipid bilayer membrane | They are cylindrical structures with a central core and regulatory particles at each end |
Mechanism | Lysosomes use hydrolytic enzymes to break down substrates | Proteasomes degrade proteins by unfolding them and threading them into the central core |
Regulation | Lysosome activity is regulated by the pH of their environment, and have an acidic interior (pH between 4.0-5.0) which amplifies activity of hydrolytic enzymes | Proteasome activity is dependent on ubiquitin ligases |