Proteolysis is the term describing the digestion of proteins by enzymes called proteases. These proteases, or other intracellular molecules, break down proteins into their constituent parts of amino acids or smaller polypeptides. Proteolysis is implicated in many different processes inside the body including digestion, intracellular degradation, cell cycle regulation, and apoptosis. In human digestion, proteins are broken down by digestive enzymes like pepsin, trypsin, chymotrypsin, and elastase. This process starts in the stomach and the smaller nutrient parts are then absorbed in the small intestine. Intracellular proteolysis is helpful in removing damaged or abnormal proteins from the inside of cells. The lysosome and the proteasome assist in this process by engulphing proteins and using proteases like cathepsins to digest them. During the cell cycle, specific proteins called cyclins are able to activate kinases that are involved in cell division. In apoptosis, or programmed cell death, certain proteases called caspases assist in the processes of apoptosis.

Anti-ITCH/AIP4 antibody binds against the target ITCH/AIP4. ITCH/AIP4 is localized on the cell membrane, in the cytoplasm, and in the nucleus. ITCH/AIP4 is an E3 ubiquitin-protein ligase and is widely expressed in many different tissues. Defects in ITCH are the cause of syndromic multisystem autoimmune disease (SMAD). Syndromic multisystem autoimmune disease is characterized by organomegaly, failure to thrive, developmental delay, dysmorphic features, and autoimmune inflammatory cell infiltration of the lungs, liver, and gut. Anti-TRIM11 antibody binds against the target TRIM11. TRIM11 (ripartite motif containing 11) is an E3 ubiquitin-protein ligase that promotes the degradation of certain ubiquitinated proteins. TRIM11 is localized in the cytoplasm and nucleus of cells and is ubiquitously expressed in many tissues in the body. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1, a B-box type 2, and a coiled-coil region.