COMPLEXATION BETWEEN BARU PROTEIN ISOLATED AND NARINGIN – AN ENERGY AND DYNAMIC VIEW

The baru (Dipteryx alata Vog.) protein isolate (BPI) is a promising candidate to form supramolecular structures for carrying bioactive compounds, e.g. naringin (NR). The thermodynamics and the kinetics (Table 1) of BPI-NR nanocomplex formation were determined by surface plasmon resonance at pH 7.4 and 298.15 K.

Table 1. Thermodynamic and kinetic parameters of BPI-NR nanocomplexes formation at 25 °C.
Thermodynamic stable complex Activated complex
k_a= 1.85∙104 L∙M-1s-1 Association pathway Dissociation pathway
k_d= 0.472∙s-1 E_act= -84.35 kJ∙mol-1 E_act= -0.73 kJ∙mol-1
K_b= 3.92∙104 L∙M-1 〖∆H〗^‡= -86.83 kJ∙mol-1 〖∆H〗^‡= -3.21 kJ∙mol-1
〖∆H〗^°= -78.54 kJ∙mol-1 〖∆G〗^‡= 48.66 kJ∙mol-1 〖∆G〗^‡= 74.88 kJ∙mol-1
〖∆G〗^°= -26.22 kJ∙mol-1 〖T∆S〗^‡= -135.49 kJ∙mol-1 〖T∆S〗^‡= -86.82 kJ∙mol-1
〖T∆S〗^°= -52.32 kJ∙mol-1

Around 18.500 BPI-NR nanocomplex were formed per second, while 47% of these nanostructures dissociated per second. Desolvation process did not contribute to BPI-NR interaction suggesting that NR interacts with the hydrophilic region of BPI proteins1. The entropic decrease shown by association and dissociation processes demonstrated that BPI-NR activated and thermodynamic stable complexes formation occurs with a conformational and configuration free degree reduction. The negative ΔH° and TΔS° values showed that the BPI-NR formation was due to hydrogen bonds and dispersion interactions. Our results are fundamental to managing the application of plant-based proteins as supramolecular nanocarriers.
Keywords: kinetics; thermodynamics; activated complex; plant-based proteins
Acknowledgments: CAPES, CNPq, and Fapemig.

References
1. Rezende, J. P. et al. (2022) Application of Congo red dye as a molecular probe to investigate the kinetics and thermodynamics of the formation processes of arachin and conarachin nanocomplexes. Food Chemistry 2022, 384, 132485.