Matrix metalloproteinase 28 also known as epilysin is an enzyme that in humans is encoded by the MMP28 gene. Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix for both normal physiological processes, such as embryonic development, reproduction and tissue remodeling, and disease processes, such as asthma and metastasis. This gene encodes a secreted enzyme that degrades casein. Its expression pattern suggests that it plays a role in tissue homeostasis and in wound repair. Alternative splicing of this gene results in multiple transcript variants.