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【答案】应助回帖
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咸鱼(金币+5, EPI+1): good~ 2011-07-15 13:07:05
大米小麦(金币+1): 2011-08-02 08:59:33
PAL的提取与活性的测定
按照Lister等的方法[19]并略有改进. 0.5 g甘薯材料加入5 mL的提取液[0•2 M硼酸盐缓冲液(pH8.8), 0.018 Mβ-巯基乙醇], 0.1 g PVPP(以去除酚类物质对颜色的干扰),加少量石英砂,于-20℃预冷的研钵中冰浴研磨, 4层纱布过滤.滤液经4℃, 15 000 g离心20 min,取上清液作为粗酶液,用于PAL活性测定.
取1 mL粗酶液加2 mL蒸馏水再加1 mL反应底物(0•02 M的L-苯丙氨酸),对照不加底物,加1mL蒸馏水. 34℃恒温水浴30 min, 加0.5 mL 35%的三氯乙酸(TCA)终止反应. 12 000 g离心10 min去除变性蛋白,于290 nm波长处测定吸光度. 以1 mL反应液每小时在290 nm处吸光度变化0.01为1个酶活单位, 用U表示
----- Li YP. The correlation between anthoeyanidin accumulation and activities of enzymes involved in anthoeyanidin biosynthesis in puple-fleshed sweetpotato[Ipomoea batatas(L.)Lam.][D]. Southwest University, 2010.(in chinese)
----Lister CE, Lancaster JE. Developmental changes in enzymes of flavonoid biosynthesis in the skins of ted and green apple cultivars [J]. Journal of the Science of Food and Agriculture, 1996, 71: 313-320. |
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