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林产化学与工业 ›› 2004, Vol. 24 ›› Issue (2): 52-56.

• 研究报告 • 上一篇    下一篇

大豆脂肪氧合酶的提取及影响酶活因素的研究

蔡琨, 方云, 夏咏梅, 石玉刚, 徐一铭   

  1. 江南大学 化学与材料工程学院, 江苏 无锡 214036
  • 收稿日期:2003-09-26 修回日期:1900-01-01 出版日期:2004-06-30 发布日期:2004-06-30
  • 通讯作者: E-mail:fangyunzhou@hotmail.com

EXTRACTION OF SOYBEAN LIPOXYGENASE AND FACTORS AFFECTING ITS ENZYME ACTIVITY

CAI Kun, FANG Yun, XIA Yong-mei, SHI Yu-gang, XU Yi-ming   

  1. School of Chemical and Material Engineering, Southern Yangtze University, Wuxi 214036, China
  • Received:2003-09-26 Revised:1900-01-01 Online:2004-06-30 Published:2004-06-30

摘要: 试验了从低温脱脂大豆粉中提取脂肪氧合酶(LOX)的几种方法,研究了其部分酶学性质。结果表明,直接用水浸提得到的粗酶液的总酶活最高,每10g豆粕达到6.71×107U,酶比活为8.61×105U/mL粗酶液。经盐析法或共沉淀法提纯后,总酶活的损失达55%~60%。经碱溶-酸沉-二次盐析得到的LOX的酶比活最高,达到9.42×107U/g酶粉。游离LOX的稳定性较差,室温下放置7d后酶活下降79%。pH值7~9为LOX的最佳作用范围,在pH值9时酶活性最高。外加无机盐、糖类、多元醇或有机电解质均可以提高酶的储存稳定性和热稳定性,室温下乙二胺四乙酸二钠、草酸钠、乙酸钠及氯化钙对LOX活性均有较好的稳定作用。添加质量分数为1%乙二胺四乙酸二钠的酶液在42d后酶活仍保持原来的80%左右,经50℃热处理60min后酶活仅损失6%。

关键词: 大豆脂肪氧合酶, 提取, 酶活

Abstract: Lipoxygenase(LOX) can catalyze oxygenation of the(Z,Z)-1,4-pentadiene moiety of polyunsaturated fatty acids into enantiomeric hydroperoxide fatty acids with(Z,E)-conjugated diene moiety.In this paper,several methods were used for extracting LOX from defatted soybean powder,and LOX activity was measured.Experiment results show that the total enzyme activity 6.71×107 U/10 g(defatted soybean flour) obtained by water-leaching is the highest with corresponding specific enzyme activity 8.61×105 U/mL(enzyme preparation).The loss of enzyme activity is more than 1/2 after two salting-out steps or coprecipitation process.Specific activity of LOX 9.42×107 (U/g)(powdered enzyme) obtained by alkali-dissolving and acid-leaching followed by two salting-out steps is the highest of all.Free LOX loses 79% of its activity sharply at room temperature after 7 days, indicating that low storage temperatures to maintain high enzyme activity is preferred.At pH value 9,LOX exhibits the highest enzyme activity.Addition of some salts,sugar,polyol or organic electrolytes,especially EDTA-Na2 can increase the storage stability and thermostability of LOX.By addition of 1%(mass ratio) EDTA-Na2,the activity of LOX was kept 80% of the original after 42 day,and only 6% activity was lost by heat treatment at 50℃ for 60 min.

Key words: soybean lipoxygenase, extraction, enzyme activity

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