Molecular interaction of 2-mercaptobenzimidazole with catalase reveals a potentially toxic mechanism of the inhibitor

• This work established the binding mode of MBI with CAT on molecular level.
• The mechanism was explored by multiple spectroscopic and molecular docking methods.
• MBI can inhibit CAT activity and trigger conformational changes in CAT.
• MBI can spontaneously bind into the CAT interface of chains B and C.

2-Mercaptobenzimidazole (MBI) is widely utilized as a corrosion inhibitor, copper-plating brightener and rubber accelerator. The residue of MBI in the environment possesses a potential risk to human health. In this work, the toxic interaction of MBI with the important antioxidant enzyme catalase (CAT) was investigated using spectroscopic and molecular docking methods under physiological conditions. MBI can spontaneously bind with CAT with one binding site through hydrogen bonds and van der Waals forces to form MBI-CAT complex. The molecular docking study revealed that MBI bound into the CAT interface of chains B and C, which led to some conformational and microenvironmental changes of CAT and further resulted in the inhibition of CAT activity. This present study provides direct evidence at a molecular level to show that exposure to MBI could induce changes in the structure and function of the enzyme CAT.

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