Interaction between bovine serum albumin and chitooligosaccharides: I. Molecular mechanism

The interaction between chitooligosaccharides (COS2-6) and bovine serum albumin (BSA) is worthy of investigation, which provides support for improving the physical properties (gelling, foaming, and emulsifying) of food proteins via COS addition and in vivo research on COS bioactivity. Component analysis indicated that COS2 and COS3 were enriched in the COS2-6-BSA precipitate. The fluorescence binding constant (1.73 × 103 M−1), ΔG of isothermal titration calorimetry (-6.7 kJ/mol), and the predicted ΔG of molecular docking (−10 to −5 kJ/mol) confirmed the weak interaction of COS2-6-BSA. Quartz crystal microbalance dissipation and molecular docking indicated that electrostatic and hydrophobic interactions were the main stabilization forces. Molecular docking showed that the predicted ΔG of COS2-6 to BSA decreased with the increasing degree of polymerization. This work clarified the weak and selective interaction between COS2-6 and BSA via various methods, which is useful for the food application of COS.