比较液氮研磨样品与蛋白抽提液研磨样品对6种提取橡胶树叶片转化酶方法的效果.结果表明:液氮研磨法对转化酶活性影响很大,特别是中性/碱性转化酶和细胞壁结合的酸性转化酶已基本失活,而可溶性酸性转化酶活性丧失也比较严重.利用蛋白抽提液研磨样品,用Hepes-NaOH法提取的可溶性转化酶的酶活性最高,达472.44 μmol (glucose)/[g (FW)·h]；虽然磷酸-柠檬酸法获得的粗酶液的蛋白含量较低,但其酶活性高达441.61 μmol( glucose)/[g( FW)·h];Tris-HCl法提取的细胞壁结合酸性转化酶的酶活性最高,达35.83 μmol( glucose)/[g(FW)·h].从转化酶的比活力看,磷酸-柠檬酸法最佳,所提取的叮溶性转化酶比活力约为Hepes-NaOH法的4倍.本研究结果为进一步完善橡胶树叶片转化酶的提取方法提供重要的指导意义.%Six methods were investigated in extracting invertase from the leaves of rubber tree(Hevea brasiliensis Muell. Arg)by two ways of grinding leaves: liquid nitrogen and extraction buffer. Grinding leaves in liquid nitrogen seriously destroyed the activities of invertases, especially those of neutral/alkaline invertase and cell wall-bound invertase which were totally inactivated. In comparison, the way of grinding leaves in extraction buffers was suitable for extracting various types of invertase. After the leaves were ground in extraction buffers, the activity of crude soluble invertase extracted by Hepes -NaOH method revealed to be the highest, being 472.44 u.mol (glucose )/[g (FW) o h]. Despite low protein yields obtained by phosphate -citrate method, the resulting invertase activity was as high as 441.61 μmol (glucose)/[g(FW) ·h]. Regarding the cell wall-bound invertase, Tris-HCl method was the most suitable, resulting in invertase activity of 35.83 μmol (glucose )/[g (FW)·h]. With regard to specific enzymatic activity, the phosphate-citrate method was the most appropriate, with specific activity of soluable invertases about four times as much as the Hepes-NaOH method. The results presented here wouldcontribute to developing more effective extraction methods for various types of invertases from rubber leaves.
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