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Updated: Mar 9, 2026

The Use of a β-lactamase-based Conductimetric Biosensor Assay to Detect Biomolecular Interactions
Published on: February 1, 2018
Trypsin and trypsin inhibitor bind milk beta-lactoglobulin: Protein-protein interactions and morphology
P Chanphai1, H A Tajmir-Riahi1
1Department of Chemistry-Biochemistry and Physics, University of Québec at Trois- Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada.
Abstract:
Conjugation of trypsin and trypsin inhibitor with milk beta-lactoglobulin (b-LG) was studied in aqueous solution at physiological pH. Multiple spectroscopic methods and transmission electron microscopy (TEM) were used to characterize protein-protein interactions and protein morphology. Thermodynamic analysis ΔH (-24 to -11kJMol-1), ΔS (-30 to -5JMol-1K-1) and ΔG (-12 to -10kJMol-1) showed that protein-protein interactions occur via H-bonding and van der Waals contacts. The binding affinity was trypsin>trypsin inhibitor with Ktrypsin-b-LG=9.8 (±1)×104M-1 and Ktrypsininhibitor-b-LG=7.5 (±0.7) x 103M-1. Transmission electron microscopy showed major changes in protein morphology upon protein-protein interactions.
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