[Study on interaction between sulfonylurea herbicides and catalase by fluorescence spectroscopy]

The binding of Sulfonylurea herbicides to catalase in aqueous solution was studied using fluorescence spectroscopy. It was shown that herbicides have a strong ability to quench the catalase 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 chlorsufuron, K=8.69 x 10(5) L x mol(-1) and n = 1.16; for metsufuron methyl, K = 1.01 x 10(6) L x mol(-1) and n = 1.21; and for bensufuron methyl, K = 3.52 x 10(3) L x mol(-1), n = 0.77. It is clear that the binding of metsufuron methyl with catalase is stronger than that of chlorsufuron, while the binding of chlorsufuron stronger than that of bensufuron methyl.