• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied and Environmental Microbiology >Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicolaStrain BA
【24h】

Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicolaStrain BA

机译：乳酸细菌食肉杆菌piscicolaStrain BA中的两种新的糖基水解酶的表征

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Three genes with homology to glycosyl hydrolases were detected on a DNA fragment cloned from a psychrophilic lactic acid bacterium isolate,Carnobacterium piscicola strain BA. A 2.2-kb region corresponding to an α-galactosidase gene, agaA, was followed by two genes in the same orientation, bgaB, encoding a 2-kb β-galactosidase, and bgaC, encoding a structurally distinct 1.76-kb β-galactosidase. This gene arrangement had not been observed in other lactic acid bacteria, including Lactococcus lactis, for which the genome sequence is known. To determine if these sequences encoded enzymes with α- and β-galactosidase activities, we subcloned the genes and examined the enzyme properties. The α-galactosidase, AgaA, hydrolyzespara-nitrophenyl-α-d-galactopyranoside and has optimal activity at 32 to 37°C. The β-galactosidase, BgaC, has an optimal activity at 40°C and a half-life of 15 min at 45°C. The regulation of these enzymes was tested in C. piscicolastrain BA and activity on both α- and β-galactoside substrates decreased for cells grown with added glucose or lactose. Instead, an increase in activity on a phosphorylated β-galactoside substrate was found for the cells supplemented with lactose, suggesting that a phospho-galactosidase functions during lactose utilization. Thus, the two β-galactosidases may act synergistically with the α-galactosidase to degrade other polysaccharides available in the environment.
机译：在从嗜冷乳酸菌分离株Piscicola菌株BA克隆的DNA片段上检测到三个与糖基水解酶同源的基​​因。对应于α-半乳糖苷酶基因agaA的2.2 kb区域，然后是两个方向相同的基因，分别是bgaB和2gab，BgaB编码2 kbβ-半乳糖苷酶，bgaC编码结构不同的1.76 kbβ-半乳糖苷酶。在其他乳酸菌（包括乳酸乳球菌）中尚未观察到这种基因排列，其基因组序列是已知的。为了确定这些序列是否编码具有α-和β-半乳糖苷酶活性的酶，我们将这些基因亚克隆并检查了酶的特性。 α-半乳糖苷酶AgaA可水解对硝基苯基-α-d-吡喃半乳糖苷，在32至37°C时具有最佳活性。 β-半乳糖苷酶BgaC在40°C时具有最佳活性，在45°C时具有15分钟的半衰期。这些酶的调节已在C. piscicolastrain BA中进行了测试，并且对于添加了葡萄糖或乳糖的细胞而言，α-和β-半乳糖苷底物的活性均降低。相反，发现补充有乳糖的细胞在磷酸化的β-半乳糖苷底物上的活性增加，表明磷酸-半乳糖苷酶在乳糖利用期间起作用。因此，两个β-半乳糖苷酶可以与α-半乳糖苷酶协同作用，以降解环境中可用的其他多糖。

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