Aprotinin (Traskolan) a broad-spectrum serine protease inhibitor, inhibiting the activity of a number of different esterases and proteases, including trypsin, chymotrypsin, kallikrein, plasmin, tissue plasminogen activator, and tissue and leukocytic proteinases.

Trypsin:0.06 pM(Kd), Chymotrypsin:9.5 nM(Kd), Kallikrein:0.8 nM(Kd), Trypsinogen:2 μM(Kd)

Aprotinin is an antifibrinolytic molecule that inhibits trypsin and related proteolytic enzymes. In cell biology, aprotinin is used as an enzyme inhibitor to prevent protein degradation during lysis or homogenization of cells and tissues. In the presence of aprotinin, the fibrinolytic activity is inhibited concentration dependently and the coagulation time is prolonged. Aprotinin is an effective inhibitor of the contact (intrinsic) coagulation pathway in vitro[2].

Aprotinin inhibits clot lysis in vitro as well as rat-tail bleeding time in vivo and prolongs coagulation time in human plasma. In a rat arteriovenous shunt model, aprotinin reduces thrombus weight [2].

Substrates and kinases are diluted in 50?mM Tris/HCl (pH?7.5), 0.1% 2-mercaptoethanol, 0.1?mM EGTA and 10?mM magnesium acetate. Reactions are initiated with [γ-32P]ATP (2500 c.p.m./pmol) to a final concentration of 0.1?mM and terminated after 15?min at 30°C by the addition of SDS and EDTA (pH?7.0) to final concentrations of 1.0% (w/v) and 20?mM respectively. After heating for 5?min at 100°C and separation by SDS/PAGE, the phosphorylated proteins are detected by autoradiography.

Mouse G8-1 myoblasts are plated DMEM + 20% FBS (maintenance medium), in which they remain undifferentiated. When cells reach approximately 40-50% confluence, different protease inhibitors are added to the culture media and cells are incubated overnight. Cells are then switched to differentiation-promoting media (DMEM + 10% horse serum ± protease inhibitor) and incubated for 7 days. (Only for Reference)