食品科学 ›› 2011, Vol. 32 ›› Issue (17): 262-268.doi: 10.7506/spkx1002-6630-201117055

• 生物工程 • 上一篇    下一篇

发酵乳杆菌细胞壁蛋白酶的分离纯化及酶学性质研究

朱 姁1,潘道东1,2,*   

  1. 1.南京师范大学 国家乳品加工技术研发分中心 2.宁波大学生命科学与生物工程学院
  • 发布日期:2011-08-30
  • 基金资助:
    国家自然科学基金项目(30972130);江苏省科技支撑计划项目(BE2009366);浙江省重大科技专项(2010C12015)

Purification and Enzymatic Properties of Cell Envelope Protease from Lactobacillus fermentum

ZHU Xu 1,PAN Dao-dong1,2,*   

  1. (1. Branch of National Dairy Processing Technology Developing Center, Nanjing Normal University, Nanjing 210097, China; 2. Faculty of Life Science and Biotechnology, Ningbo University, Ningbo 315211, China )
  • Published:2011-08-30

摘要: 研究分离纯化发酵乳杆菌细胞壁蛋白酶(cell envelope proteinase,CEP)的方法及其酶学性质。用50mmol/L Tris-HCl缓冲液(pH7.8)悬浮菌体,进行超声波破碎,细胞质量浓度为0.06g/mL,破碎功率330W,工作220次(工作时间3s,间隔时间5s),离心取上清液即为粗酶液。60%硫酸铵沉淀,Sephacryl S-300 HR凝胶层析,Native-PAGE割胶回收纯化发酵乳杆菌的CEP。用纯化的CEP 酶解脱脂乳,酶解液ACE(angiotensin I-converting enzyme)抑制率为50%。SDS-PAGE检测CEP分子质量为32.5kD,最适酶反应温度为41℃,最适酶反应pH值为8.0。Mg2+、Co2+、Ca2+对CEP活性有激活作用;Zn2+、Ni2+、PMSF、EDTA对CEP活性有抑制作用,说明CEP为丝氨酸蛋白酶且酶的活性中心结构的维持与金属离子有关。

关键词: 发酵乳杆菌, 细胞壁蛋白酶, 分离纯化, 酶学性质

Abstract: The purification process of cell envelope protease (CEP) from Lactobacillus fermentum was explored in this paper. Cells were suspended in 50 mmol/L Tris-HCl (pH 7.8) and subjected to ultrasonication (cell concentration of 0.06 g/mL, ultrasonic power of 330 W, ultrasonic treatment time of 3 s with intermission of 5 s, and repeated ultrasonic treatment number of 220). The supernatant was collected, precipitated with 60% saturated (NH4)2SO4 solution and separated by Sephacryl S-300 HR chromatography. The active protease was recovered from Native-PAGE gel. The ACE inhibitory rate of purified CEP was 50%. The molecular mass of purified CEP estimated by SDS-PAGE was approximately 32.5 kD. Maximum activity was reached at pH 8.0 and 41℃. The activity of CEP could be activated by Mg2+, Co2+ and Ca2+ and inhibited by Zn2+, Ni2+ and PMSF, suggesting that CEP belongs to serine protease. On the other hand, its activity could also be inhibited by EDTA, suggesting that CEP is a metallopeptidase.

Key words: Lactobacillus fermentum, cell envelope protease, purification, enzymatic properties

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