食品科学

• 生物工程 • 上一篇    下一篇

黑豆脂氧合酶的制备及其酶学活性的鉴定

李 茹1,崔晓东2,李玉英2,李 晨1,王转花1,2,*   

  1. 1.山西大学生命科学学院,山西 太原 030006;
    2.山西大学 化学生物学与分子工程教育部重点实验室,山西 太原 030006
  • 出版日期:2016-05-15 发布日期:2016-05-18

Preparation and Identification of a Black Soybean Lipoxygenase

LI Ru1, CUI Xiaodong2, LI Yuying2, LI Chen1, WANG Zhuanhua1,2,*   

  1. 1. College of Life Science, Shanxi University, Taiyuan 030006, China; 2. Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, Shanxi University, Taiyuan 030006, China
  • Online:2016-05-15 Published:2016-05-18

摘要:

从黑豆种子中分离纯化1 种黑豆脂氧合酶——bsLOX,对其酶学活性及降解花色苷等性质进行初步研究。采用缓冲液抽提、硫酸铵沉淀、透析、阳离子交换层析及凝胶层析等方法纯化出具有β-葡萄糖苷酶活性的bsLOX;分别以亚油酸钠和对硝基苯基-β-D-吡喃葡萄糖苷(p-nitrophenyl β-D-glucopyranoside,pNPG)为反应底物鉴定bsLOX的脂氧合酶活性和β-葡萄糖苷酶活性。从黑豆种子中纯化获得的bsLOX在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electropheresis,SDS-PAGE)图谱显示单一条带,分子质量约为95 kD。酶活性分析表明,纯化的bsLOX以亚油酸钠为底物时,酶活力为13 U/mL;当以pNPG为底物在405 nm波长处检测到了对硝基苯酚的生成,从而推测bsLOX具有β-葡萄糖苷酶活性。高效液相色谱实验结果表明bsLOX可以降解花色苷(矢车菊素-3-O-葡萄糖苷、矮牵牛素-3-O-葡萄糖苷)为花色素(矢车菊素、矮牵牛素)。由于降解作用不完全,继而发现花色素能抑制bsLOX的酶活性。bsLOX是黑豆中的一种兼具β-葡萄糖苷酶功能的蛋白质,而花色素可能是天然的bsLOX抑制剂。

关键词: 黑豆, 脂氧合酶, &beta, -葡萄糖苷酶活性, 花色苷, 花色素

Abstract:

Objective: To extract and purify black soybean lipoxygenase (bsLOX) containing β-glucosidase activity and
investigate its anthocyanins-degrading properties and enzymatic activity. Methods: Purification of bsLOX was carried
out by buffer extraction, ammonium sulfate precipitation, dialysis, cation exchange chromatography and gel filtration
chromatography. The activities of lipoxygenase and β-glucosidase in bsLOX were analyzed by using sodium linoleate and
p-nitrophenyl β-D-glucopyranoside (pNPG) as substrates, respectively. An LOX from black soybean seeds was obtained,
which showed a single band in SDS-PAGE, with approximate molecular weight of 95 kD. The purified protein had a
lipoxygenase activity of approximately 13 U/mL, and could produce nitro phenol using pNPG as substrate as detected at
405 nm, suggesting that bsLOX had β-glucosidase activity. HPLC results showed that bsLOX could only degrade part of
anthocyanins (cyanidin-3-O-glucoside and petunidin-3-O-glucoside) into aglycone anthocyanidins (cyanidin and petunidin)
and glucose; in turn, the residual anthocyanidins could inhibit the activity of bsLOX. Conclusion: LOX in black soybean
may be a kind of protein with a variety of enzymatic functions, while anthocyanidins may be a natural bsLOX inhibitor.

Key words: black soybean, lipoxygenase, β-glucosidase activity, anthocyanin, anthocyanidins

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