Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP’s are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. The enzyme encoded by this gene degrades type IV and V collagens. Studies in rhesus monkeys suggest that the enzyme is involved in IL-8-induced mobilization of hematopoietic progenitor cells from bone marrow, and murine studies suggest a role in tumor-associated tissue remodeling.
In Western blot analysis, the inactive form (pro-MMP9) and the active form (mature MMP9) are found at the following molecular heights:
• Pro-MMP9 (inactive form): ~92 kDa
• Maturation MMP9 (active form): ~82 – 84 kDa
The difference in weight is due to proteolytic cleavage of the prodomain (the inhibitory portion of the protein). Depending on the cell type and species (e.g., in mice), glycosylation may cause the bands to migrate slightly higher, between 90 kDa and 105 kDa.