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A1153 Sigma

Aprotinin from bovine lung

lyophilized powder, 3-8 TIU/mg solid

Synonym: Trasylol, Trypsin inhibitor (basic)



Frequently Asked Questions

Frequently Asked Questions are available for this Product.


Aprotinin is largely used as an inhibitor of trypsin.


1, 5 mg in glass bottle

10, 25, 100, 250 mg in poly bottle

Preparation Note

This product is a lyophilized powder with activity of 3-8 TIU/mg of solid powder. Aprotinin is freely soluble in water (>10 mg/mL) and in aqueous buffers of low ionic strengths. Dilute solutions tend to be less stable than concentrated ones, though solution stability also depends on pH. Aprotinin is relatively stable against denaturation - only thermolysin has been found capable of degrading it at 60-80°C. Sterilizaiton of Aprotinin can be achieved through filtration by a 0.2 μm filter.

Unit Definition

One Trypsin Inhibitor Unit (TIU) will decrease the activity of two trypsin units by 50%, where one trypsin unit will hydrolyze 1.0 μmole 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.

Biochem/physiol Actions

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.

Price and Availability

Amplified Detection

Amicon Ultra Centrifugal Filters
Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 
Protocols & Articles


Enzymatic Assay of Aprotinin

The scope of this procedure is all products that have a specification for Aprotinin activity.
Keywords: Enzymology, Extinction coefficient

Peer-Reviewed Papers


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