Investigation of the Interaction between N-Acetyl-l-Cysteine and Ovalbumin by Spectroscopic Studies, Molecular Docking Simulation, and Real-Time Quartz Crystal Microbalance with Dissipation.

This study investigated the interaction between N-acetyl-l-cysteine (NAC) and ovalbumin (OVA) using multispectroscopic technology, molecular docking, and quartz crystal microbalance with dissipation (QCM-D). Fluorescence intensity and UV absorption of OVA were decreased substantially upon the addition of NAC. The calculated Kq values were obtained at 298, 304, and 310 K for 13.48, 15.59, and 17.50 (× 1012 L mol-1), respectively, suggesting that the static quenching was dominated. Thermodynamic parameters such as ΔH (-150.58 kJ mol-1), ΔS (-433.51 J mol-1 K-1), and ΔG values (-21.39 kJ mol-1), combined with molecular docking and QCM-D data, showed that the interaction was spontaneous and van der Waals and hydrogen bonding were identified as the main driving forces. FTIR and CD results showed that the α-helix content of OVA increased from 2.8 to 22.9%, and the β-sheet decreased from 0.2 to 21.9% in the presence of 5 and 10 μM NAC, respectively, compared to the pure OVA, respectively.