钒酸盐和脲对锯缘青蟹碱性磷酸酶的抑制作用

The Inhibition Effects of Oxovanadate Compounds and Urea on Green Crab( Scylla serrata) Alkaline Phosphatase

钒酸盐 (偏钒酸钠、钒酸钠、偏钒酸铵、联吡啶过氧钒酸钠 )和脲作为养殖环境的污染物对锯缘青蟹 (Scylla serrata)碱性磷酸酶的酶活力有明显的抑制作用 ,抑制程度随着抑制剂浓度的增大而增强 .钒酸盐对酶的抑制类型均为竞争性抑制 ,而脲为非竞争性抑制 ;在脲浓度低于 7.0 mol/ L时 ,2 5℃与脲处理 2 .5h的酶的抑制失活作用是可逆的 .钒酸盐和脲对酶有协同抑制作用 .

The effects of sodium orthovanadte,ammonium metavanadate,sodium metavanadate,sodium ( 2 ,2′- bipyridine) oxodiperoxovanadate and urea on the activity of green crab alkaline phosphatase have been studied to monitor and prevent pollutants from contaminating the aquatic- cultivation water.The results showed that vanadates and urea inhibited the enzyme obviously,leading to reversible inactivation. The equilibrium constants for inhibitors binding with the enzyme have been determined.The descending potency of five inhibitors is sodium metavanadate,ammonium metavanadate,sodium orthovanadte,sodium ( 2 ,2′- bipyridine) oxodiperoxovanadate and urea successively. The obtained results show that four oxovanadte compounds are all competitive inhibitors,while urea is uncompetitive inhibitor.Inactivation of the enzyme resulting from being incubated with buffer containing1 ～ 7mol/ L of urea for 2 .5 hour at 2 5℃ is reversible when the enzyme was diluted in the normal assay system.The synergistic effect between sodium metavanadte and urea has been observed clearly as well.