Aprotinin is a single chain polypeptide (58 amino-acids) crosslinked by three disulfide bridges, showing competitive and reversible inhibiton of proteolytic and esterolytic activity. Aprotinin forms stable complexes with, and blocks the active sites of serine protease enzymes. It is found in bovine…

A reversible inhibitor of serine proteases such as trypsin (Ki = 0.06 pM), chymotrypsin (Ki = 9.5 nM), and kallikrein (Ki = 0.8 nM); widely used as a protein purification tool to prevent proteases present in tissue samples from degrading the protein of interest.