• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Novel methods for carbon and nitrogen determinations in biological samples and for the bacterial biosynthesis of carbon-14-vitamin B12.
【24h】

Novel methods for carbon and nitrogen determinations in biological samples and for the bacterial biosynthesis of carbon-14-vitamin B12.

机译：用于测定生物样品中碳和氮以及细菌生物合成碳-14-维生素B12的新方法。

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 elemental composition of compounds, especially of carbon and nitrogen, is of considerable interest in many areas of science. Accurate and precise carbon measurements have become even more important as Accelerator Mass Spectrometry (AMS) has been increasingly used for nutrition metabolism studies to follow the fate of a 14C-labeled nutrient or xenobiotic. A method was developed for simultaneous carbon and nitrogen measurements in biological samples and utilizes an internal standardization and isotope ratio mass spectrometry (IRMS). Carbon demonstrated linearity (r = 0.9989) over the range of atom % 13C values from close to natural abundance at 1.1 to a large degree of enrichment at 10.4. The slope of the line is 0.812x +/- 0.0191 and the y-intercept was 0.176 +/- 0.120. Nitrogen also demonstrated linearity (r = 0.9999) over the range of atom % 15N values from close to natural abundance at 0.369 to a large degree of enrichment at 3.56. The slope of the line is 0.948 +/- 0.00183 and the y-intercept was 0.0267 +/- 0.00355.; A second project was the biosynthesis of 14C-vitamin B 12 to be used as a radioactive tracer for future human metabolism studies using AMS. The biosynthesis of 14C-vitamin B12 in Salmonella typhimurium is performed in a one-pot procedure. Fermentation is conducted with aeration and agitation in a single flask for 24 hours in the dark at 37°C with shaking at 250 RPM. Dimethylbenzimidazole (DMB) is used by the bacteria as a precursor to the imidazole moiety of the vitamin B12 molecule. 14C-DMB was synthesized from 14C-formic acid and dimethylphenylenediamine, and the resulting product added to the fermentation flask. The 14C-vitamin B12 was purified by HPLC and the identification confirmed through comparison of UV/vis spectra and LC/MS spectra with those of cyanocoblamin standards. The total mass yield of vitamin B12 produced was 25 mug (18.6 nmoles) and 880 nCi, corresponding to a specific activity of 47.3 mCi/mmol.
机译：在许多科学领域中，化合物，尤其是碳和氮的元素组成令人关注。随着加速器质谱（AMS）越来越多地用于营养代谢研究，以追踪14 C标记的营养物或异种生物的命运，准确和精确的碳测量变得越来越重要。开发了一种用于同时测量生物样品中碳和氮的方法，该方法利用了内部标准化和同位素比质谱（IRMS）。碳在原子％13C值的范围内显示线性（r = 0.9989），从1.1的接近自然丰度到10.4的大量富集。直线的斜率是0.812x +/- 0.0191，y轴截距是0.176 +/- 0.120。在原子百分比15N值的范围内，氮也表现出线性（r = 0.9999），从接近自然丰度（0.369）到高度富集度（3.56）。线的斜率是0.948 +/- 0.00183，y轴截距是0.0267 +/- 0.00355。第二个项目是14C-维生素B 12的生物合成，将其用作放射性示踪剂，用于未来使用AMS进行的人体代谢研究。一锅法进行鼠伤寒沙门氏菌中14C-维生素B12的生物合成。在37°C的黑暗条件下，在250 RPM摇动下，在单个烧瓶中通气和搅拌进行发酵24小时。细菌使用二甲基苯并咪唑（DMB）作为维生素B12分子咪唑部分的前体。由14C-甲酸和二甲基苯二胺合成14C-DMB，并将所得产物加到发酵瓶中。通过HPLC纯化14C-维生素B12，并通过将UV / vis光谱和LC / MS光谱与氰钴胺素标准品进行比较来确认鉴定。产生的维生素B12的总质量产率为25马克（18.6毫摩尔）和880 nCi，对应的比活为47.3 mCi / mmol。

著录项

  • 作者

    Carkeet, Colleen.;

  • 作者单位

    University of California, Davis.;

  • 授予单位 University of California, Davis.;
  • 学科 Chemistry Agricultural.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 81 p.
  • 总页数 81
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农业化学;
  • 关键词

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