Description
Serpina 4, also called Kallistatin, is a protein that in humans is encoded by the SERPINA4 gene. It is a member of the serpin superfamily and represents a major inhibitor of human tissue kallikrein in circulation. Kallistatin is a serine proteinase inhibitor (serpin) and a heparin-binding protein. It is localized in vascular smooth muscle cells and endothelial cells of blood vessels, suggesting that it may be involved in the regulation of vascular function