Molybdenum Disulfide Quantum Dots Inhibit Catalase Activity via Conformational Alteration: Insights from Multispectral Analysis and Molecular Simulations

This study investigates the interaction mechanism between molybdenum disulfide quantum dots (MoS 2 QDs) and bovine liver catalase (BLC) and its effect on enzyme activity using multispectral analysis and molecular simulations. The results demonstrated that MoS 2 QDs induced noncompetitive inhibition of BLC by binding to its allosteric sites (binding constant: 1.27 × 10 5 L∙mol −1 at 298 K), reducing maximum catalytic velocity with altering the Michaelis-Menten constant. Stable 1:1 non-fluorescent complex formation, primarily driven by van der Waals forces, triggers significant conformational alterations in BLC, including a decrease in α -helix content (from 21.73% to 17.33%) and an increase in random coil structure. Molecular docking identifies 14 binding residues (e.g., aspartate-156, leucine-158, arginine-430) distal to the active site, with a binding free energy of −4.79 kcal·mol −1 . Thermal denaturation studies reveal that MoS 2 QDs reduce the thermal stability of BLC (Δ T m  = 5.3 °C). These findings elucidate the machanism bu which MoS 2 QDs inhibit BLC activity through structural perturbation, providing critical insights for the biological safety evaluation of nanomaterials.