Serpins are the largest family of protease inhibitors and are fundamental for the control of proteolysis in multicellular eukaryotes. Most eukaryote serpins inhibit serine or cysteine proteases, however, noninhibitory mem-bers have been identified that perform diverse functions in processes such as hormone delivery and tumour metastasis. More recently inhibitory ser-pins have been identified in prokaryotes and unicellular eukaryotes, never-theless, the precise molecular targets of these molecules remains to be identified
