The extracellular matrix is composed of many nonliving materials that surround cells in multicellular organisms and provide structural support for the cell as well as performing other important functions (depending on the type of cell that is surrounded). Plants, animals, and fungi have extracellular matrices. The extracellular matrix is made of glycoproteins, collagens, proteoglycans, and glycosaminoglycans. The ECM has many different functions including cell adhesion, cell behavior regulation, and cell growth and development regulation. The degradation and remodeling of the extracellular matrix is mostly controlled by ECM enzymes called matrix metalloproteinases or MMPs. MMPs have three major structural domains each with a specific function. The catalytic domain can destabilize and activate the hydrolysis of peptide bonds on target substrates. The linker peptide domain is rich in proline residues and is involved in substrate selection. The C-terminal domain is involved in protein to protein interactions that can help to bind the ECM enzyme to the target substrate.

The anti-KLK5 antibody is also known as the anti-Kallikrein 5 antibody. This antibody binds against the kallikrein 5 target which is expressed in skin, breast tissue, testis tissue, and the brain. It is thought to be involved in desquamation. Desquamation occurs naturally in skin tissues however, it can also be pathogenic. This is characterized by thick layers of skin peeling off and leaving a dry, scaly appearance. The anti-hemopexin antibody binds to heme in blood and transports it to the liver for it to be broken down. After which, the iron is recovered and used in other applications and the free hemopexin is returned into general circulation to start the process over again.