Matrix metallopeptidase 9 (MMP-9), also known as 92 kDa type IV collagenase, 92 kDa gelatinase or gelatinase B (GELB), is a matrixin, a class of enzymes that belong to the zinc-metalloproteinases family involved in the degradation of the extracellular matrix. In humans the MMP9 gene encodes for a signal peptide, a propeptide, a catalytic domain with inserted three repeats of fibronectin type II domain followed by a C-terminal hemopexin-like domain. Thrombospondins, intervertebral disc proteins, regulate the effective levels of MMP-2 and -9, which are key effectors of ECM remodeling. MMP-9 has been found to be associated with numerous pathological processes, including cancer, immunologic and cardiovascular diseases. This kit is designed to measure MMP-9 (92 kDa pro- and 82 kDa active forms but not the 65 kDa form).