T1021

Trypsin inhibitor from Glycine max (soybean)

Isoelectric focusing marker, pI 4.6

• Synonym(s): SBTI
• CAS Number: 9035-81-8
• EC Number: 232-906-9
• MDL number: MFCD00082103
• NACRES: NA.77

Properties

• biological source: Glycine max (soybean)
• Quality Level: 200
• form: powder
• mol wt: 20,100 Da
• technique(s): isoelectric focusing (IEF): suitable
• pI: 4.6
• solubility: balanced salt solution: 1 mg/mL; concentrate: >10 mg/mL, hazy, amber-yellow; phosphate buffer: 10 mg/mL; water: 10 mg/mL; serum-free medium: soluble
• shipped in: ambient
• storage temp.: −20°C

Description

Biochem/physiol Actions

This inhibitor acts against trypsin, and chymotrypsin and plasmin to a lesser extent. It will also inhibit proteases with mechanisms similar to trypsin, plasma kallikrein and coagulation Factor X. The trypsin inhibitor will not act against metalloproteases, tissue-baseed kallikrein, acid proteases, or thio proteases. This inhibitor acts by forming a 1:1 stoichiometric complex with the protease active site, and then cleaving a single arginine-isoleucine bond on the inhibitor. The inhibition is both reversible and pH dependent.

Components

The soybean trypsin inhibitor is a monomeric protein containing 181 amino acid residues in a single polypeptide chain crosslinked by two disulfide bridges.

Unit Definition

One trypsin unit = A₂₅₃ of 0.001 per minute with N-alpha-benzoyl-L-arginine ethyl ester (BAEE) as substrate at pH 7.6 at 25 °C.

Preparation Note

The trypsin inhibitor is soluble in water and phosphate buffers at 10 mg/mL. It is soluble in balanced salt solutions at 1 mg/mL and in serum-free media. Concentrated solutions greater than 10 mg/mL may be hazy and have a yellow to amber color. After trypsinizing cells, resuspend in 1 mL trypsin inhibitor solution at 1 mg/mL for every mL of trypsin solution used for dissociation. The cell suspension should then be centrifuged at 1000 rpm, forming a cell pellet.

Solutions can retain activity when stored short-term at 2-8° C. Solutions are stable in frozen aliquots at -20°C.