瑞士乳杆菌X-脯氨酰-二肽酰基-氨基肽酶的分离纯化及酶学性质  

Purification and Characterization of X-Prolyl Dipeptidyl Aminopeptidase from Lactobacillus helveticus

作　　者：郭宇星[1] 祝倩[1] 朱坤[1] 周慧敏[1] 孙杨赢[1,2] 曾小群[1,2] 潘道东[1,2] 

机构地区：[1]南京师范大学金陵女子学院,江苏南京210097 [2]宁波大学海洋学院,浙江宁波315211

出　　处：《食品科学》2013年第17期156-160,共5页Food Science

基　　金：国家自然科学基金青年科学基金项目(31101314);江苏省自然科学基金项目(BK2011787);江苏省高校自然科学基金项目(13KJB550013);南京师范大学特聘教授;高层次人才科研启动基金项目(184070H2B08);浙江省自然科学基金项目(LQ12C20003);宁波市科技局创新基金项目(2010C92024);宁波市自然科学基金项目(2012A610145)

摘　　要：提取并纯化瑞士乳杆菌X-脯氨酰-二肽酰基-氨基肽酶(Pep X),并对其酶学性质进行研究。采用超声波破碎瑞士乳杆菌菌体获得含有Pep X的粗酶液,粗酶液经过硫酸铵沉淀、Sephacryl S-300 HR层析、非变性-聚丙烯酰胺凝胶电泳法切胶回收蛋白纯化瑞士乳杆菌Pep X。纯化后Pep X经SDS-PAGE测定分子质量并研究酶学性质。得到电泳纯的PepX,酶比活力62.24U/mg,单体分子质量大约26kD,最适酶反应pH7.0,最适酶反应温度37℃。Co2+对PepX有激活作用,Zn2+、Ni2+、Mn2+、Fe3+对Pep X有强烈的抑制作用,金属蛋白酶抑制剂EDTA、丝氨酸蛋白酶抑制剂PMSF对Pep X有一定的抑制作用,说明Pep X为金属依赖性的丝氨酸肽酶。X-prolyl dipeptidyl aminopeptidase （Pep X） from Lactobacillus helveticus was purified and characterized. The Pep X was released from Lactobacillus helveticus cells by sonication. The cell-free extract was purified by ammonium sulfate precipitation, chromatographed on Sephacryl S-300 HR and native-PAGE gel. The molecular mass of purified Pep X was measured by SDS-PAGE. The specific activity of the enzyme was 62.24 U/mg. The purified Pep X had monomer molecular mass of approximately 26 kD. Optimal activity was observed at pH 7.0 and 37 ℃. It was activated by Co2＋ and inhibited by Zn2＋, Ni2＋, Mn2＋ and Fe3＋. It was a metallopeptidase and serine proteinase that was inhibited by EDTA and PMSF.

关 键 词：X-脯氨酰-二肽酰基-氨基肽酶(Pep-X) 纯化 酶学性质 

分 类 号：TS201.3[轻工技术与工程—食品科学]