...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied Microbiology and Biotechnology >Homologous expression and biochemical characterization of the arylsulfatase from Kluyveromyces lactis and its relevance in milk processing
【24h】

Homologous expression and biochemical characterization of the arylsulfatase from Kluyveromyces lactis and its relevance in milk processing

机译：乳酸克鲁维酵母中芳基硫酸酯酶的同源表达，生化特性及其在牛奶加工中的相关性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The industrial manufacturing process of lactose-free milk products depends on the application of commercial beta-galactosidase (lactase) preparations. These preparations are often obtained from Kluyveromyces lactis. There is a gene present in the genome of K. lactis which should encode for an enzyme called arylsulfatase (EC 3.1.6.1). Therefore, this enzyme could also be present in beta-galactosidase preparations. The arylsulfatase is suspected of being responsible for an unpleasant "cowshed-like" off-flavor resulting from the release of p-cresol from milk endogenous alkylphenol sulfuric esters. So far, no gene/functionality relationship is described. In addition, no study is available which has shown that arylsulfatase from K. lactis is truly responsible for the flavor generation. In this study, we cloned the putative arylsulfatase gene from K. lactis GG799 into the commercially available vector pKLAC2. The cloning strategy chosen resulted in a homologous, secretory expression of the arylsulfatase. We showed that the heretofore putative arylsulfatase has the desired activity with the synthetic substrate p-nitrophenyl sulfate and with the natural substrate p-cresol sulfate. The enzyme was biochemically characterized and showed an optimum temperature of 45-50 A degrees C and an optimum pH of 9-10. Additionally, the arylsulfatase was activated by Ca2+ ions and was inactivated by Zn2+ ions. Moreover, the arylsulfatase was inhibited by p-cresol and sulfate ions. Finally, the enzyme was added to ultra-heat treated (UHT) milk and a sensory triangle test verified that the arylsulfatase from K. lactis can cause an unpleasant "cowshed-like" off-flavor.
机译：无乳糖乳制品的工业生产过程取决于商业β-半乳糖苷酶（乳糖酶）制剂的应用。这些制剂通常得自乳酸克鲁维酵母。乳酸克鲁维酵母基因组中存在一个基因，该基因应编码一种称为芳基硫酸酯酶的酶（EC 3.1.6.1）。因此，该酶也可能存在于β-半乳糖苷酶制剂中。怀疑该芳基硫酸酯酶是由牛奶内源性烷基酚硫酸酯中释放出对甲酚引起的令人不快的“类似牛粪”的异味的原因。迄今为止，没有描述基因/功能关系。另外，尚无研究表明乳酸克鲁维酵母中的芳基硫酸酯酶真正负责风味的产生。在这项研究中，我们从乳酸克鲁维酵母GG799克隆了假定的芳基硫酸酯酶基因到市售载体pKLAC2中。选择的克隆策略导致芳基硫酸酯酶的同源分泌表达。我们表明，迄今推定的芳基硫酸酯酶对合成底物对硝基苯硫酸盐和天然底物对甲酚硫酸盐具有所需的活性。对该酶进行了生化表征，显示出最适温度为45-50 A摄氏度，最适pH为9-10。此外，芳基硫酸酯酶被Ca2 +离子激活，而被Zn2 +离子灭活。此外，芳基硫酸酯酶被对甲酚和硫酸根离子抑制。最后，将该酶添加到超高温处理（UHT）牛奶中，并进行了感官三角测试，证实来自乳酸克鲁维酵母的芳基硫酸酯酶会引起令人不快的“牛w状”异味。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号