摘要:
以莱茵衣藻的Rubisco 突变体69-12Q+,68-4PP+ 和野生型2137+ 为材料,分析比较了Rubisco 粗酶在不同温度、不同pH条件下的初始活性,25℃时的总活性,酶的最适温度,最适pH和粗酶的活化百分数。用Kostov 和McFadden 的作图法测定了3 个品系Rubisco 纯化酶在25℃时的CO2/O2 特征因子Ω值,结果69-12Q+ 的Ω= 13;68-4PP+ 的为54;2137+ 则为61.上述结果显示Rubisco 大亚基上氨基酸的替换, 必然引起Rubisco 结构的变化,从而引起Rubisco 酶催化特性改变。作图法测定Ω值操作简便、快速、准确,优于传统方法。
Abstract:
We have investigated the kinetic parameters of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and determine CO2/O2 specificity factor (Ω).Initial activities of rude enzyme of Rubisco in various temperature,various pH, and total enzyme activities at 25℃ were assayed among the Rubisco mutants 69-12Q+,68-4PP+ and wild type 2137+ in Chlamydomonas reinhardtii.The rude enzyme's optimum temperature,optimum pH and percentage of activation were determined.Analyses of CO2/O2 specificity factor Ω of purified Rubisco were conducted with Kostov and McFadden's graphical method.The Ω values for 69-12Q+,68-4PP+ and 2137+ are 13,54,and 61 respectively.Our results indicated that subtle perturbation of Rubisco subunit may exert signification effects on its catalytic properties and the Ω value can be altered by the manipulation of Rubisco molecular.Graphical determination of the CO2/O2 specificity factor is superior in simplicity, celerity and accuracy to traditional methods.
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