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A3428 Sigma

Aprotinin from bovine lung

lyophilized powder, 3-8 TIU/mg solid, BioReagent, suitable for cell culture

Synonym: Trasylol, Trypsin inhibitor (basic)

  • CAS Number 9087-70-1

  • Empirical Formula (Hill Notation) C284H432N84O79S7

  • Molecular Weight 6511.44

  •  EC Number 232-994-9

  •  MDL number MFCD00130541

  •  eCl@ss 32190102



Related Categories Biochemicals and Reagents, Cell Culture, Cell Dissociation, Core Bioreagents, Enzyme Inhibitors,
product line   BioReagent
form   lyophilized powder
mol wt   mol wt ~6,500
solubility   H2O: 5 mg/mL
suitability   suitable for cell culture
storage temp.   2-8°C
Gene Information   cow ... PTI(404172)



Aprotinin is largely used as an inhibitor of trypsin.


10, 25 mg in poly bottle

100, 250 mg in glass bottle

Preparation Note

This product is a lyophilized powder that has been cell culture tested. It has an activity of 3-7 TIU/mg.

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.

When benzoyl-L-arginine ethyl ester (BAEE) is used as substrate one BAPNA unit is approx. 45BAEE μmolar units at pH8.0 at 25°C or approx. 9,000 BAEE A253 units at pH7.6 at 25°C.

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.

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 


Certificate of Analysis

Certificate of Origin

Protocols & Articles


Common Cell Culture Problems: Cell Clumping

Cells in suspension may attach to one another and form clumps for a variety of reasons. The most common cause of cell clumping is the presence of free DNA and cell debris in the culture medium, which...
Keywords: Adhesion, Apoptosis, Cell culture, Cell disruption, Culture media, Environmental, Flow cytometry

Common Cell Culture Problems: Cell Death

There is perhaps nothing more frustrating to a cell culturist than removing a dish from the incubator only to find that it’s full of dead cells. Getting to the bottom of the problem can be very chall...
Keywords: Antibiotics, Apoptosis, Autophagy, Buffers, Cell culture, Cell disruption, Cryopreservation, Culture media, Environmental, Enzyme activity, Filtration, Metabolism, Peptide synthesis, Reductions

Common Cell Culture Problems: Cell Line Cross-Contamination and Misidentification

A few years after scientists working at Johns Hopkins established the first human cell line using cervical epithelial cells (HeLa) from cancer patient Henrietta Lacks in the early 1950s, it was obser...
Keywords: Cancer, Cell culture, Cryopreservation, Forensic, Genetic, Phase transitions, Polymerase chain reaction

Common Cell Culture Problems: Contamination

Overview Types of Contamination Common Causes and Prevention of Contaminants    Microbial (bacteria, fungi, yeast)    Mycoplasma    Viral Contamination    Chemical Contamination General Tips and Tech...
Keywords: Antibiotics, Antifungals, Apoptosis, Buffers, Cell attachment, Cell culture, Culture media, Detergents, Eliminations, Environmental, Filtration, Fluorescent microscopy, Gene expression, Indicators, Metabolism, Microscopy, Polymerase chain reaction, Sterilizations

Common Cell Culture Problems: Poor Attachment of Adherent Cells

Optimal cell attachment in vitro requires the interaction of healthy cells with a wide range of cell-derived attachment molecules present in media, serum, and supplements. Cultureware surfaces are fr...
Keywords: Buffers, Cell attachment, Cell culture, Culture media, Decarboxylations, Environmental, Growth factors, Lipid peroxidation, Peroxidations, Precipitation, Reductions, Respiration

Common Cell Culture Problems: Precipitates

When contamination is ruled out, turbidity in cell culture media is often explained by the precipitation of metals, proteins, and other media components. Precipitates can be harmful to cell health, a...
Keywords: Antibiotics, Cell culture, Culture media, Desiccation, Evaporation, Filtration, Microscopy, Nucleic acid denaturation, Precipitation, Purification


Common Cell Culture Problems: Poor Cell Growth

Ensuring adequate cell growth is a critical part of collecting accurate data with cell cultures. Cells can be cultured in suspension, or as a monolayer that attaches to cultureware, such as a flask, ...
Keywords: Antibiotics, Apoptosis, Buffers, Cell attachment, Cell culture, Condensations, Cryopreservation, Culture media, Evaporation, Filtration, Microscopy, Phase transitions, Reductions

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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