Serine protease inhibitor (Serpin)

Serine protease inhibitors, or serpins, constitute a broad superfamily of proteins that regulate the activity of serine proteases through a unique suicide-substrate mechanism. By undergoing a dramatic conformational change upon protease binding, they permanently inactivate their target enzymes, thereby maintaining homeostatic control over critical pathways such as blood coagulation, inflammation, and the complement system [1][2]. Deficiencies or mutations in these inhibitors lead to a group of disorders known as serpinopathies, characterized by either a loss of inhibitory function, such as emphysema in alpha-1 antitrypsin deficiency, or the toxic accumulation of misfolded protein polymers in the liver [3][4]. Clinically, purified or recombinant serpins are used as replacement therapies to restore the protease-antiprotease balance in patients with hereditary deficiencies [5][6]. Additionally, synthetic small-molecule inhibitors are employed to manage conditions like acute pancreatitis or viral infections by mimicking the inhibitory action of these endogenous proteins [5]. Understanding the balance between these inhibitors and their cognate proteases is essential for managing various inflammatory, vascular, and neurodegenerative disorders [7]. This target entry is marked as incorrect because it refers to a broad class of proteins rather than a single specific molecular target.

Other names

SerpinsSerine proteinase inhibitorsSPIsEndogenous protease inhibitorsProtease inhibitors (serine type)

Serpins function through a unique suicide-substrate mechanism where they undergo a massive conformational change upon cleavage by a target protease, trapping the enzyme in a stable, covalent complex and permanently inactivating it [1][7].