【摘要】 为了研究稀土金属离子对烟叶铜锌超氧化物歧化酶的作用规律,消除活体烟叶中其他因素的影响,试验采用离体方法,利用硫酸铵盐析分级分离、乙醇-氯仿沉淀除杂、丙酮再沉淀分级等方法,得到含铜锌超氧化物歧化酶的酶液。研究了不同浓度的La3+、Sm3+、Y3+、Ce3+对铜锌超氧化物歧化酶活性的影响,结果显示,在浓度为0～250 mg/L范围内,La3+、Sm3+、Y3+、Ce3+都能使铜锌超氧化物歧化酶的活性先降低后升高再降低。但在相同浓度下,对酶活性影响最大的是Y3+,而Sm3+的影响次之。铜锌超氧化物歧化酶的活性受这4种离子影响的变化幅度在20%左右,清除超氧自由基的能力变化较大。更多还原

【Abstract】 The superoxide dismutase in tobacco leaves played a vital role in anti-oxidation.In order to eliminate various environmental factors,the in vitro method was applied in the present investigation to study changing trends of the copper-zinc superoxide dismutase activity caused by rare earth ions.The enzyme solution of copper-zinc superoxide dismutase from tobacco leaves was obtained by using ammonium sulphate to form different levels of precipitates and by using chloroform and alcohol to isolate the impurities and acetone for further clean-up.The effects of La3+,Sm3+,Y3+ and Ce3+ with different concen-trations on copper-zinc superoxide dismutase were studied.The results showed that the activity of copper-zinc superoxide dismutase demonstrated a decreasing trend first,then an increasing trend and finally a decreasing trend in response to the increasing La3+,Sm3+,Y3+ or Ce3+ supply from 0 to 250 mg / L.At the same concentration,however,the change of copper-zinc superoxide dismutase activity under the influence of Y3+ was strongest,and then the Sm3+.The changes in the enzyme activity under the effects of these four rare earth ions were approximately 20%,and the ability of eliminating.O2-varied considerably.更多还原