Effect of Cadmium Ion on alpha-Glucosidase: An Inhibition Kinetics and Molecular Dynamics Simulation Integration Study

α-Glucosidase is a critical metabolic enzyme that produces glucose molecules by catalyzing carbohydrates. The aim of this study is to elucidate biological toxicity of Cd²⁺ based on α-glucosidase activity and conformational changes. We studied Cd²⁺-mediated inactivation as well as conformational modulation of α-glucosidase by using kinetics coupled with simulation of molecular dynamics. The enzyme was significantly inactivated by Cd²⁺ in a reversibly binding behavior, and Cd²⁺ binding induced a non-competitive type of inhibition reaction (the K _i was calculated as 0.3863 ± 0.033 mM). Cd²⁺ also modulated regional denaturation of the active site pocket as well as overall partial tertiary structural change. In computational simulations using molecular dynamics, simulated introduction of Cd²⁺ induced in a depletion of secondary structure by docking Cd²⁺ near the saccharides degradation at the active site, suggesting that Cd²⁺ modulating enzyme denaturation. The present study elucidated that the binding of Cd²⁺ triggers conformational changes of α-glucosidase as well as inactivates catalytic function, and thus suggests an explanation of the deleterious effects of Cd²⁺ on α-glucosidase.