The Serpins: Evolution and Adaptation in a Family of Protease Inhibitors

The serpins are a superfamily of serine protease inhibitors that have undergone divergent evolution over a period of some 600 million years (Hunt and Dayhoff 1980; Carrell and Boswell 1986). The best-studied member of the family is the human plasma protein α1-antitrypsin (Carrell et al. 1982), which is now known to function primarily as an inhibitor of leucocyte elastase and for this reason is alternatively named α1-proteinase inhibitor (Travis and Salvesen 1983). Here we will retain the historical name abbreviated to antitrypsin.