绿磺隆、醚苯磺隆及其体外代谢物对乙酰乳酸合成酶的离体抑制作用

利用异源表达于酵母细胞中的小麦细胞色素P450cDNA(CYP71C6v1)研究了磺酰脲类除草剂绿磺隆、醚苯磺隆的代谢作用。结果表明,代谢产物5-羟基绿磺隆和5-羟基醚苯磺隆能够抑制乙酰乳酸合成酶(ALS酶)活性,且代谢产物与母体化合物绿磺隆、醚苯磺隆抑制ALS酶活性的IC50值差异小,但是代谢产物在茎叶喷雾小麦和菜豆时,均未表现出活性。绿磺隆及其代谢产物抑制小麦ALS酶活性的IC50值分别为7.1×10-9和7.9×10-9mol/L,抑制菜豆ALS酶活性的IC50分别为3.6×10-9和4.1×10-9mol/L;醚苯磺隆及其代谢产物抑制小麦ALS酶活性的IC50分别为4.6×10-9和5.3×10-9mol/L,抑制菜豆ALS酶活性的IC50分别为4.7×10-9和4.9×10-9mol/L。结果表明,在磺酰脲类分子苯环5位上进行结构改造,有可能得到高活性的化合物。

Inhibition of Acetolactate Synthase Activity by Chlorsulfuron, Triasulfuron and Their Metabolites in vitro

The metabolism of two sulfonylurea herbicides chlorsulfuron and triasulfuron was investigated by using wheat cytochrome P450 cDNA(CYP71C6v1) which expressed in yeast.The results showed that chlorsulfuron and triasulfuron were hydroxylated at 5-position on the phenyl ring.The difference in IC₅₀ of parent compound and 5-hydroxy metabolites to acetolactate synthase(ALS) was small.However,their metabolites injured neither wheat nor bean,when applied as post-emergence treatment.The IC₅₀ of chlorsulfuron and its metabolites to wheat ALS were 7.1×10^-9 and 7.9×10^-9 mol/L,respectively,and to bean ALS were 3.6×10^-9 and 4.1×10^-9mol/L,respectively.The IC₅₀of triasulfuron and its metabolites to wheat ALS were 4.6×10^-9 and 5.3×10^-9 mol/L,respectively,and to bean ALS were 4.7×10^-9 and 4.9×10^-9 mol/L,respectively.These results suggested that proper groups at 5-position on phenyl ring of sulfonylurea molecule might possess high herbicidal activity.