食品科学 ›› 2019, Vol. 40 ›› Issue (24): 101-109.doi: 10.7506/spkx1002-6630-20181110-121

• 生物工程 • 上一篇    下一篇

粘质沙雷氏菌膜结合葡萄糖酸脱氢酶的分离纯化及其酶学特性

王贝贝,李昊聪,孙文敬,崔凤杰,王大明,,钱静亚,齐向辉   

  1. (1.江苏大学食品与生物工程学院,江苏 镇江 212013;2.江西省德兴市百勤异VC钠有限公司,江西 德兴 334221;3.江南大学生物工程学院,江苏 无锡 214122)
  • 出版日期:2019-12-25 发布日期:2019-12-24
  • 基金资助:
    国家自然科学基金面上项目(31571885);江苏高校优势学科建设工程资助项目(PAPD); 国家高技术研究发展计划(863计划)项目(2012AA022103); “十三五”国家重点研发计划重点专项(2017YFC1600806);江西省科技计划项目(赣知发[2015]64号); 江西省创新团队建设计划项目(20142BCB24024);江西省科技平台建设计划项目(2010DTZ01900); 德兴市科技计划项目(德科发[2015]44号)

Isolation, Purification and Characterization of Membrane-Bound Gluconate Dehydrogenase from Serratia marcescens

WANG Beibei, LI Haocong, SUN Wenjing, CUI Fengjie, WANG Daming,, QIAN Jingya, QI Xianghui   

  1. (1. School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China;2. Jiangxi Dexing Parchn Sodium Isovitamin C Co. Ltd., Dexing 334221, China;3. School of Biotechnology, Jiangnan University, Wuxi 214122, China)
  • Online:2019-12-25 Published:2019-12-24

摘要: 经超声破碎细胞、TritonX-114相分离、盐析、DEAE-sepharose离子交换层析和Hydroxyapatite吸附层析等步骤,从2-酮基葡萄糖酸(2-keogluconic acid,2KGA)生产菌株粘质沙雷氏菌JUIM03中获得比活力91.43 U/mg、纯化倍数160.4 倍的膜结合葡萄糖酸脱氢酶(gluconate dehydrogenase,GADH)。研究结果表明,粘质沙雷氏菌膜结合GADH由3 个亚基组成,其分子质量分别为65.0、45.0 kDa和23.0 kDa左右,是一种含有细胞色素C的黄素蛋白,能够催化氧化葡萄糖酸为2KGA。粘质沙雷氏菌膜结合GADH的最适反应温度为40 ℃,最适反应pH 5.0,在30 ℃以下、pH 5.0~6.0的条件下较为稳定;该酶具有严格的底物特异性,只有在D-葡萄糖酸作为底物时才具有催化活性,其Km值为1.33 mmol/L;一些金属离子(如Fe3+、Cu2+和Zn2+)、有机溶剂(乙醇、异丙醇、甲醇和丙酮)、变性剂(十二烷基硫酸钠和巯基乙醇)以及有机酸(草氨酸和草酸)对膜结合GADH的催化活性具有明显的抑制作用。研究为粘质沙雷氏菌2KGA生物合成的过程优化与控制提供了一定的理论依据。

关键词: 粘质沙雷氏菌, 2-酮基葡萄糖酸, 膜结合葡萄糖酸脱氢酶, 分离纯化, 酶学特性

Abstract: An intracellular membrane-bound gluconate dehydrogenase (GADH) with specific activity of 91.43 U/mg and purification fold of 160.4 was purified from Serratia marcescens JUIM03, a 2-ketogluconic acid (2KGA)-producing strain, using a five-step procedure, including ultrasonication, Triton X-114 phase separation, ammonium sulfate fractionation, DEAE-sepharose fast flow and hydroxyapatite column chromatography. The results showed that the membrane-bound GADH consisted of three subunits with molecular masses of 65.0, 45.0 and 23.0 kDa respectively. It was a flavin protein-containing cytochrome C catalyzing the oxidation of gluconic acid to 2KGA. The optimum reaction temperature and pH were 40 ℃ and 5.0 kDa, respectively. It was stable below 30 ℃ and in the pH range of 5.0–6.0, and exhibited strict substrate specificity for D-gluconate with a Km of 1.33 mmol/L. Several metal ions including Fe3+, Cu2+ and Zn2+, organic solvents including ethanol, isopropanol, methanol and acetone, denaturants including SDS and mercaptoethanol, and organic acids including oxamic acid and oxalic acid had significant inhibitory effects on the enzyme activity. This study provides a theoretical basis for the optimization and control of 2KGA biosynthesis in Serratia marcescens.

Key words: Serratia marcescens, 2-ketogluconic acid, membrane-bound gluconate dehydrogenase, purification, enzymatic properties

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