Metalloproteinases are a group of at least 25 Zn2 + -dependent exopeptidases , whose primary function is to modulate the extracellular environment by proteolysis of the protein components of extracellular matrix , membrane receptors and cytokines . These enzymes are synthesized as precursor cells and released into the extracellular space where they are activated by proteolytic cleavage of the propeptide region . Metalloproteinases are tightly regulated at the level of transcription and translation, and by specific tissue inhibitors ( tissue inhibitors of metalloproteinases , TIMPs ) . Under physiological conditions, metalloproteinases regulate processes related to the development and ensure the homeostasis of the organism. Excessive activation of extracellular proteolysis is observed in a number of acute and chronic pathological processes ( ischemia , multiple sclerosis , cancer ) . Understanding the mechanisms which regulate the activity of metalloproteases and their interaction with specific inhibitors , modulators or substrates may have not only cognitive importance , but also the potential for the development of practical importance in the therapeutic treatment of certain pathological conditions .