Interaction between triazine herbicide and catalase by fluorescence spectrum

The binding of triazine herbicide to catalase in aqueous solution was studied using fluorescence spectroscopy. It was shown that the herbicide has a strong ability to quench the CAT fluorescence mainly through a static quenching procedure. The binding constant K and the number of binding site n were calculated according to the fluorescence quenching results. For prometryn, K = 6.17×10~6 L·mol-1 and n was 1.45; for prometon, K = 2.12·10~5 L·mol-1 and n was 1.19. Based on the mechanism of energy transfer, the distances between acceptor herbicide and CAT were obtained. The distances are r (prometryn) = 0.140 run and r (prometon) = 0. 155 nm. It is clear that the binding of prometryn with catalase is stronger than that of prometon. It is inferred that the binding site between herbicides and catalase was Tyr-214.