Aprotinin is a reversible inhibitor of serine proteases such as trypsin (Ki = 0.06 pM), chymotrypsin (Ki = 9.5 nM), and kallikrein (Ki = 0.8 nM). It is a much weaker inhibitor of thrombin (Ki = 0.1-0.8 mM) and trypsinogen (Ki = 2 μM). Aprotinin also competitively inhibits nNOS and iNOS with Ki values of 50 and 78 μM, respectively. Aprotinin is widely used as a protein purification tool to prevent proteases present in tissue samples from degrading the protein of interest.
A potent protease inhibitor.Aprotinin acts as a reversible serine protease blocking and a binding agent. It is widely employed as an inhibitor of trypsin. It is also used as a proteolytic inhibitor in radioimmunoassays of polypeptide hormones. It is involved in the purification of urokinase, trypsin, and chymotrypsin on immobilized aprotinin. Further, it is used in the quantification of kallikrein activity in mixtures of esterases and proteases.
Aprotinin is largely used as an inhibitor of trypsin.
1 kg of parotid of cattle, which were freed of fat and flesh are comminuted in
a meat chopper and twice extracted with 5 L of acetone. The acetone was
removed as far as possible by sucking off and the moist material is digested
for 2.5 hours in 1.2 L of 1 N acetic acid and 2.8 L of 96% ethanol at 50°C.
The filtrate containts about 230.000 inactivator units.
The alcoholic solution is concentrated to 1.2 L by evaporating in vacuo and
shaken with an equal amount of ether. Dark coloring matters and residues of
fat are thus dissolved. The aqueous phase is now mixed with acetone until a
precipitate occurs and the dissolved in dilute acetic acid. The solution is
brought to a weakly alkaline pH by addition of ammonia. It is then centrifuged
and the inactivator is precipitated with five times the amount of ethanol. The
yield amounts to about 180.000 kallikrein inactivator units in 0.4-0.5 g of
substance.
Trypsin inhibitor, pancreas type from bovine lung. It is known as Pancreatic trypsin inhibitor (BPTI). Aprotinin, also known as pancreatic trypsin inhibitor and trypsin-kallikrein inhibitor, is found to be expressed in lungs, spleen, liver, and pancreas. It is also found to be present in the free form in calf serum.
Aprotinin is a competitive serine protease inhibitor that forms stable complexes with and blocks the active sites of enzyme. This binding is reversible, and most aprotinin-protease complexes will dissociate at extreme pH levels >10 or <3. Structurally, Aprotinin is a monomeric globular protein derived from bovine lung that consists of 58 amino acids, arranged in a single polypeptide chain with three crosslinking disulfide bridges.
Experimental reproductive effects. When heated to decomposition it emits toxic fumes of NOx and SOx.
1. henry da, carless pa, moxey aj, et al. anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion. cochrane database syst rev 2007; 4: cd001886.2. levi m, cromheecke me, de jonge e, et al. pharmacological strategies to decrease excessive blood loss in cardiac surgery: a meta-analysis of clinically relevant endpoints. lancet 1999; 354: 1940-7.3. sedrakyan a, treasure t, elefteriades ja. effect of aprotinin on clinical outcomes in coronary artery bypass graft surgery: a systematic review and meta-analysis of randomized
