Interaction Mechanism between 2-Mercaptothiazoline and Catalase

Key words: 
• 2-mercaptothiazoline /
• catalase /
• multi-spectroscopic techniques /
• molecular docking

Abstract: 2-Mercaptothiazoline (2-MT) is a kind of widely used corrosion inhibitor and brightener. The residue of 2-MT in the environment is potentially harmful. To evaluate the toxicity of 2-MT at the protein level, the effects of 2-MT on catalase (CAT) were investigated by multiple spectroscopic techniques and molecular modeling. The enzyme activity experiment indicated that the CAT activity was inhibited by 2-MT. Molecular docking results revealed that 2-MT bound into the CAT active site, which further led to some secondary structure and micro-environmental changes of CAT. According to the fluorescence results, the quenching mechanism of fluorescence of CAT by 2-MT was a static quenching procedure. The number of binding sites n, the binding constant k and the thermodynamic parameters at different temperatures were also measured. The results indicated that 2-MT can interact with CAT to form a complex mainly by van der Waals' interactions and hydrogen bonds. In this paper, we studied the toxic mechanism between 2-mercaptothiazoline and protein at the molecular level, which will consequently be significant to learn the toxic effect of pollutants.