Serpin E3
Serpin E3 is a poorly characterized secreted-type member of the clade E serpins, the small branch that also includes PAI-1 and protease nexin I. The human SERPINE3 gene shows restricted expression, with reported transcription in kidney and testis, and functional data on its inhibitory target remain sparse. The conserved serpin architecture suggests it can trap serine proteases via a reactive-center loop, but no physiological substrate has been validated. Clade E serpins collectively regulate extracellular proteolysis in fibrinolysis, tissue remodeling and cell migration. Recombinant Serpin E3 is therefore valuable for biochemical screening and for clarifying whether this orphan serpin retains genuine inhibitory activity.
