The different techniques like spectroscopy and fluorescence quenching were used to study the interactive effect of carbendazim (CARB) and catalase (CAT) at the molecular level. The results showed that conditions were beneficial to the quenching mechanism at 25.0 °C, pH 7.0, while the binding constant k was 1.92 × 105 L mol-1 and the number of binding site was 1.0385. The thermodynamic parameters indicated that CARB could interact spontaneously with CAT to form a complex mainly by van der Waals' interactions and hydrogen bonds. The interaction mechanism between CARB and CAT was that the effects of CARB on CAT in soil were activated and then restore stability. However, the effects of CARB on simple CAT were activated and then inhibited.
Keywords: Carbendazim; Catalase; Fluorescence; Interaction mechanism; Quenching; Stern-Volmer.