Scholarlink

<p>A quick, noninvasive method based on <sup>31</sup>P NMR spectroscopy to measure the pH of samples containing phosphate buffer is presented. By taking advantage of all four phosphate species populated at acidic, mildly acidic, mildly alkaline and alkaline pH, the method is applicable over a wide range of pH values, from 1 to 13. This tool is most precise at pH values near the pKa values, namely from 5.8 to 8.0 and 10.6 to 13.0. To facilitate its use, a web application is presented that calculates the pH value directly from phosphate <sup>31</sup>P chemical shift (ppm) when sodium or potassium is the cation: (<a href="https://rmni.iqf.csic.es/software/31phnmr/">https://rmni.iqf.csic.es/software/31phnmr/</a>). In addition, the potential of this approach to monitor reactions which generate or consume H<sup>+</sup> is illustrated by following the hydrolysis of GTP catalyzed by Ras-like protein in brain 1a (Rab1a), an essential protein linked to Parkinson’s disease and tuberculosis. The intrinsic GTPase rate of Rab1a is found to be 3.3 ± 0.8·10<sup>− 3</sup> min at 37&#xa0;°C, which places Rab1a amoung the Rabs with slow GTPase rates and the longer lived “active” GTP-bound states.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

In sample pH measurement by 31P phosphate NMR: application to measure the intrinsic GTPase activity of Rab1a

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月25日

查看全文
  • David Pantoja-Uceda,
  • Douglas V. Laurents

摘要

A quick, noninvasive method based on 31P NMR spectroscopy to measure the pH of samples containing phosphate buffer is presented. By taking advantage of all four phosphate species populated at acidic, mildly acidic, mildly alkaline and alkaline pH, the method is applicable over a wide range of pH values, from 1 to 13. This tool is most precise at pH values near the pKa values, namely from 5.8 to 8.0 and 10.6 to 13.0. To facilitate its use, a web application is presented that calculates the pH value directly from phosphate 31P chemical shift (ppm) when sodium or potassium is the cation: (https://rmni.iqf.csic.es/software/31phnmr/). In addition, the potential of this approach to monitor reactions which generate or consume H+ is illustrated by following the hydrolysis of GTP catalyzed by Ras-like protein in brain 1a (Rab1a), an essential protein linked to Parkinson’s disease and tuberculosis. The intrinsic GTPase rate of Rab1a is found to be 3.3 ± 0.8·10− 3 min at 37 °C, which places Rab1a amoung the Rabs with slow GTPase rates and the longer lived “active” GTP-bound states.