... inhibitor serine proteases serpin The serpin ( ser ine p roteinase in hibitor) superfamily of proteins is both ancient and unique. Found in all five kingdoms of life, they are likely to have evolved from a single common ancestor — termed ‘the archeserpin’ — approximately 500 million years ago...

... enzymes encoded by mammalian genomes, membrane-anchored serine proteases (MASPs), which are expressed on the surface of epithelial cells of all major organs, are excellently suited to mediate signal transduction across the epithelia and are increasingly being recognized as important regulators...