Protein Domain : Serpin family IPR000215

Type	Family
Description	Protein protease inhibitors constitute a very important mechanism for regulating proteolytic activity. Serpins (SERine Proteinase INhibitors) belong to MEROPS inhibitor family I4, clan ID. Most serpin family members are indeed serine protease inhibitors, but several have additional cross-class inhibition functions and inhibit cysteine protease family members such as the caspases and cathepsins [ , ]. Others, such as ovalbumin, are incapable of protease inhibition and serve other functions []. The serpins are a functionally diverse family of proteins with a highly conserved structure. Members of the serpin family have been identified in a variety of organisms including animals, viruses, plants [ , ], archaea and bacteria [, ]. Vertebrate serpins are involved in fundamental biological processes such as blood coagulation, complement activation, fibrinolysis, angiogenesis, inflammation and tumor suppression []. A fungal serpin (celpin) has also been characterised and it is thought to protect the cellulose-degrading apparatus (cellulosome) against proteolytic degradation [].Serpins share a highly conserved core structure that is critical for their functioning as serine protease inhibitors [ , ]. Inhibitory serpins comprise several α-helix and β-strands together with an external reactive centre loop (RCL) containing the active site recognised by the target enzyme. The conserved native fold consists of three β-sheets (A, B and C) surrounded by α-helices (up to nine, A-I) and the RCL. Serpins form covalent complexes with target proteases. Their mechanism of protease inhibition is known as irreversible "trapping", in which a rapid conformational change traps the cognate protease in a covalent complex resulting in permanent inactivation of both the serpin and its cognate proteinase [].
Short Name	Serpin_fam