Aprotinin is a competitive serine protease inhibitor that inhibits trypsin, chymotrypsin, kallikrein and plasmin. Aprotinin forms stable complexes with and blocks the active sites of enzymes. Binding is reversible with most aprotinin-protease complexes, dissociating at pH >10 or <3. Effective concentration is equimolar with protease.Activity: ≥ 3TIU/mgUnit Definition of Activity:One Trypsin Inhibitor Unit (TIU) will decrease the activity of two trypsin units by 50%, where one trypsin unit will hydrolyze 1.0umol of N-alpha-benzoyl-DL-arginine p-nitroanilide per minute at pH 7.8 and 25°C. Another commonly used unit is the KIU, with 1 TIU = 1,300 KIU.Moisture Content:≤7%Storage and Stability:Lyophilized powder is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
