【摘要】 从大豆中纯化分离得到三种大豆酯酶同工酶(Soybean Esterase isozyme,SEI)记为SEI1,SEI2和SEI3。利用SDS-聚丙烯酰胺凝胶电泳测定三种酯酶的亚基相对分子量,SEI1的亚基分子量为40.7 ku;SEI2含有两个亚基,分子量分别为37.2 ku和21.4 u;SEI3的亚基分子量为74.1 ku。催化底物α-乙酸奈酯的米氏常数Km分别为22.7,58.6和13.4μmol/L,最适温度分别为30,30和25℃,最适pH值分别为6.5,6.0和6.5。三种酯酶对农药的敏感性实验表明,SEI2对农药的敏感性最好,SEI3其次,SEI1无敏感性。故而选择SEI2作为农残检测用植物酯酶。更多还原

【Abstract】 Three soybean esterase isozymes(SEI) were purified from soybean and were separately marked as SEI1,SEI2 and SEI3.The subunits of the three isozymes were determined by SDS-PAGE.It is demonstrated that the molecular weight of SEI1 is 40.7 KDa,SEI2 has two subunits with molecular weight 37.2 KDa and 21.4 KDa,and the molecular weight of SEI3 is 74.1 KDa.The Km of SEI1 is 22.7 μmol/L,optimal temperature 30 ℃ and pH 6.5.The Km of SEI2 is 58.6 μmol/L,optimal temperature 30 ℃ and pH 6.0.The Km of SEI3 is 13.4 μmol/L,optimal temperature 25 ℃ and pH 6.5.The sensitivities to organophosphate and carbamate pesticides of the isozymes were tested.Results indicate that the sensitivity to pesticides of SEI2 is better than SEI3,and SEI1 is not sensitive to pesticides.Thus,SEI2 can be selected as the enzyme to detect pesticide residues.更多还原