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Trypsin Inhibitor from Glycine max (soybean)

BioUltra, lyophilized powder, ≥95% (Kunitz inhibitor, SDS-PAGE)

Kunitz Inhibitor
CAS Number:
EC Number:
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Quality Level

biological source

Glycine max (soybean)

product line



≥95% (Kunitz inhibitor, SDS-PAGE)


lyophilized powder

storage temp.


General description

Trypsin Inhibitor from Glycine max (soybean) also known as Kunitz trypsin inhibitor is a 21 kDa protein with a single trypsin binding reactive site.


Trypsin Inhibitor from Glycine max (soybean) has been used:
  • as a standard protein to measure the amount of endogenous trypsin inhibitor present in midgut lysate (M1) of Riptortus pedestris
  • as a standard to compare the trypsin inhibitory activity of the purified protein
  • to monitor the trypsin inhibitory activity by fractionating in MonoS cation exchange chromatography
  • as an trypsin inhibitor


5, 10, 25 mg in glass bottle

Biochem/physiol Actions

Trypsin Inhibitor from Glycine max (soybean) binds with the active site of trypsin enzyme, in a competitive inhibition manner.
Soybean trypsin inhibitor inhibits trypsin and to a lesser extent chymotrypsin and plasmin. It forms a 1:1 stoichiometric complex with trypsin. Upon formation of this complex, trypsin may cleave a single arginine-isoleucine bond in the inhibitor. Dissociation of this complex may yield the modified form or the native inhibitor. At the optimal pH for trypsin binding (pH 8.0), the association constant is ≥ 10x108.

Unit Definition

One trypsin unit will produce a ΔA253 of 0.001 per min with BAEE as substrate at pH 7.6 at 25 °C; reaction volume 3.2 ml, 1 cm light path.

Preparation Note

Further purification of T9128 yielding an electrophoretically pure Kunitz inhibitor with increased activity.
Trypsin inhibitor is soluble in water and phosphate buffers at concentrations of 10 mg/ml or higher. Solutions at higher concentrations may be hazy and have a yellow to amber color.

Analysis Note

One mg will inhibit ≥1.0 mg of trypsin with activity of approx. 10,000 BAEE units per mg protein.

Other Notes

View more information on Trypsin Inhibitor.


Health hazard

Signal Word


Hazard Statements

Hazard Classifications

Resp. Sens. 1 - Skin Sens. 1

Storage Class Code

11 - Combustible Solids



Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

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Certificate of Origin

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Quantitative determination of active Bowman-Birk isoinhibitors, IBB1 and IBBD2, in commercial soymilks
Arques MC, et al.
Food Chemistry, 155, 24-30 (2014)
The selective complex behavior between soybean whey proteins and i-carrageenan and isolation of the major proteins of the soybean whey
Li X, et al.
Food Hydrocolloids, 56, 207-217 (2016)
Functional analysis of the Kunitz trypsin inhibitor family in poplar reveals biochemical diversity and multiplicity in defense against herbivores
Major IT and Constabel CP
Plant Physiology, 146(3), 888-903 (2008)
A continuous fluorometric assay for trypsin based on melittin and the noncovalent-binding-induced pyrene excimer
Xu N, et al.
Chemistry Letters (Jpn), 42(12), 1528-1530 (2013)
A midgut lysate of the Riptortus pedestris has antibacterial activity against LPS O-antigen-deficient Burkholderia mutants
Am Jang H, et al.
Developmental and Comparative Immunology, 67, 97-106 (2017)


Enzymatic Assay of Trypsin Inhibitor

This technical article described the Enzymatic Assay of Trypsin Inhibitor.

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