The purification and characterization of lipoxygenase （LOX, EC 1.13.11.12） from the green algae Enteromorpha clathrata were studied. Two components marked LOX - 1 and LOX - 2 were purified and their molecular masses...The purification and characterization of lipoxygenase （LOX, EC 1.13.11.12） from the green algae Enteromorpha clathrata were studied. Two components marked LOX - 1 and LOX - 2 were purified and their molecular masses were estimated to be 102 and 79 ku by SDS - PAGE. Both LOX - 1 and LOX - 2 were stable over the pH wide range 6.0 - 10.0 and had the optimum pH of 10.0 and 8.6, at optimum temperature of 30 and 25℃, respectively. Substrate specificities of LOX - 1 and LOX - 2 were the greatest towards linoleic acid, followed by arachidonic acid and linolenic acid. The Michaelis constant values of LOX - 1 and LOX - 2 were 0.23 and O. 20 mmol/dm^3 with the substrate of linoleic acid. The LOX activities were stimulated greatly by Ca^2＋ but inhibited by Hg2 ~ and the antioxidants such as BHA, BHT and TBHQ. The hydroperoxide products of LOX were analysed by HPLC with the substrate of methyl linoleate, and the results showed that LOX - 1 formed mainly 9-hydroperoxides while LOX - 2 formed both 9- and 13-hydroperoxides at a ratio of 24： 76.展开更多
文摘利用硅胶柱色谱、Sephadex LH-20柱色谱和HPLC等手段,从浒苔Entermorpha prolifera的甲醇提取物中分离得到了5个单体化合物。它们的结构通过波谱分析结合文献对照被鉴定为：胆甾醇（1）,13^2S-羟基脱镁叶绿素a（2）,13^2R-羟基脱镁叶绿素a（3）,13^2S-羟基脱镁叶绿素b（4）,phaeophytin a hydroperoxide（5）。化合物2-5均为首次从该种海藻中分离得到。
基金The Technology Research and Development Program ("863"Program) of China under contract No.2003AA625030.
文摘The purification and characterization of lipoxygenase （LOX, EC 1.13.11.12） from the green algae Enteromorpha clathrata were studied. Two components marked LOX - 1 and LOX - 2 were purified and their molecular masses were estimated to be 102 and 79 ku by SDS - PAGE. Both LOX - 1 and LOX - 2 were stable over the pH wide range 6.0 - 10.0 and had the optimum pH of 10.0 and 8.6, at optimum temperature of 30 and 25℃, respectively. Substrate specificities of LOX - 1 and LOX - 2 were the greatest towards linoleic acid, followed by arachidonic acid and linolenic acid. The Michaelis constant values of LOX - 1 and LOX - 2 were 0.23 and O. 20 mmol/dm^3 with the substrate of linoleic acid. The LOX activities were stimulated greatly by Ca^2＋ but inhibited by Hg2 ~ and the antioxidants such as BHA, BHT and TBHQ. The hydroperoxide products of LOX were analysed by HPLC with the substrate of methyl linoleate, and the results showed that LOX - 1 formed mainly 9-hydroperoxides while LOX - 2 formed both 9- and 13-hydroperoxides at a ratio of 24： 76.
