Alpha-2-Macroglobulin Like Protein 1 (a2ML1)

The alpha-macroglobulin (AM) superfamily of proteins contains both complement components and protease inhibitors, including A2M and A2ML1. AM proteins display a unique trap mechanism of inhibition, by which the AM inhibitor undergoes a major conformational change upon its cleavage by a protease, thus trapping the protease and blocking it from subsequent substrate binding. This protein has a peptide stretch, called the 'bait region' which contains specific cleavage sites for different proteinases. When a proteinase cleaves the bait region, a conformational change is induced in the protein which traps the proteinase. The entrapped enzyme remains active against low molecular weight substrates. Following cleavage in the bait region a thioester bond is hydrolyzed and mediates the covalent binding of the protein to the proteinase.