Purity ~98% (SDS-PAGE, HPLC). Aprotinin inhibits the activity of several proteolytic enzymes such as chymotrypsin, kallikrein, plasmin and trypsin. It is present in blood and in most tissues, with a high concentration in lung, inhibits pro-inflammatory cytokine release and maintains glycoprotein homeostasis. In platelets, aprotinin reduces glycoprotein loss (e.g., GpIb, GpIIb/IIIa), while in granulocytes it prevents the expression of pro-inflammatory adhesive glycoproteins. Aprotinin is a natural proteinase inhibitor polypeptide consisting of fifty-eight amino acids arranged in a single polypeptide chain, cross-linked by three disulfide bridges and having a molecular mass of 6512 Daltons. Aprotinin is purified by proprietary chromatographic techniques. Source: Bovine lung Molecular Weight: ~6.5kD Biological Activity: 5x10e6 IU/mg. Endotoxin Level: <0.1ng/ug