Related Experiment Video
Updated: Jul 22, 2026

The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 17, 2010
Inactivation Kinetics Study of the Kunitz Soybean Trypsin Inhibitor and the Bowman-Birk Inhibitor
van Den Hout R1, Pouw, Gruppen
1Department of Food Science, Food and Bioprocess Engineering Group, Wageningen Agricultural University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
Abstract:
The inactivation of trypsin inhibitors (TIs) in soy flour exhibits a two-phase inactivation behavior. It is sometimes assumed that this behavior is caused by a difference in the heat stabilities of the Kunitz soybean trypsin inhibitor (KSTI) and the Bowman-Birk inhibitor (BBI). Kinetics studies with KSTI and BBI in soy flour showed that this two-phase inactivation behavior of TIs could not be explained by the difference in the heat stabilities of KSTI and BBI. Inactivation of KSTI and BBI in an aqueous solution and in a starch matrix followed a first-order reaction. KSTI and BBI in a starch matrix with added cysteine showed a two-phase inactivation behavior. The existence of thiols in soy flour seems to be responsible for the two-phase inactivation of TIs in soy flour. It is suggested that TIs in soy flour are inactivated by sulfhydryl-disulfide interchange during the first inactivation phase and by heat during the second phase.
Related Concept Videos
Enzyme Inhibition
Enzyme Kinetics
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Enzymes
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
The Equilibrium Binding Constant and Binding Strength
Introduction to Enzyme Kinetics
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...

