Aprotinin from bovine lung

Application.
Aprotinin is widely used as trypsin inhibitor.

Biochemical / physiological behavior.
Aprotinin is a competitive serine protease inhibitor, which can form a stable compound enzyme with the active site of the enzyme and block it at the same time. This binding is reversible, and most aprotinin-protease complexes can be dissociated at extreme pH > 10 or < 3 levels. Structurally, aprotinin is a monomer globular protein from bovine lung, which is composed of 58 amino acids and arranged in a single polypeptide chain with three cross-linked disulfide bonds.

Unit definition.
One trypsin inhibitor unit (TIU) can reduce the activity of two trypsin units by 50%, and one of the trypsin units can hydrolyze 1 μ mol of N-α-benzoyl-DL- arginine p-nitroaniline per minute at pH 7.8 and 25 ℃. Another commonly used unit is KIU, while 1 TIU = 1300 KIU.

Points for attention in preparation.
The product is a freeze-dried powder with 3-8 TIU/mg activity of solid powder. Aprotinin is soluble in water (> 10mg / mL) and in aqueous buffers with low ionic strength. The diluent is often not as stable as the concentrate, although the stability of the solution also depends on pH. Aprotinin is relatively stable in denaturation-only thermophilic protease can degrade it at 60-80 ℃. The sterilization of aprotinin can be achieved by filtration of 0.2 μ m filter.