Unusually large deuterium discrimination during spore photoproduct formation.
Unusually large deuterium discrimination during spore photoproduct formation.
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DOI：
10.1021/jo500775b
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发表时间：
2014-06-06
期刊：
影响因子：
--
通讯作者：
Li L
中科院分区：
文献类型：
--
作者：
Ames DM;Lin G;Jian Y;Cadet J;Li L
氘标记技术在化学和生物化学反应机理研究中得到了广泛的应用，并被证明是非常有效的。然而，它往往是阻碍了不完全的标签转移，从而掩盖了机械的结论。在研究光诱导产生5-胸腺嘧啶-5，6-二氢胸腺嘧啶（通常称为孢子光产物（SP））的过程中，Cadet实验室发现SP形成中的氘转移不完全（约67%），这与Li实验室观察到的完全转移形成对比。在这里，我们研究了这种差异，重新检查SP形成使用d3-胸苷。在进行SP光化学之前，我们用不同量的未标记胸苷加标d3-胸苷。引人注目的是，我们的数据表明，反应是高度敏感的起始材料中的痕量质子化胸苷。在形成的SP中检测到多达17倍的富集，这可以解释先前观察到的三分之一的氚掺入。虽然市售的氘代试剂一般是令人满意的机械探针，我们的研究结果认为，仍然需要注意的可能干扰的痕量质子化杂质，特别是当反应产率低，大同位素歧视涉及。
The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (∼67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved.
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DOI：
10.1073/pnas.88.19.8288
发表时间：
1991-10-01
影响因子：
11.1
作者：
NICHOLSON, WL;SETLOW, B;SETLOW, P
通讯作者：
SETLOW, P
影响因子：
4.8
作者：
Pieck, J. Carsten;Hennecke, Ulrich;Carell, Thomas
通讯作者：
Carell, Thomas
影响因子：
15
作者：
Cheek, J;Broderick, JB
通讯作者：
Broderick, JB
影响因子：
4.3
作者：
Lin, Gengjie;Chen, Chun-Hsing;Li, Lei
通讯作者：
Li, Lei
影响因子：
56.9
作者：
Grove, Tyler L.;Benner, Jack S.;Booker, Squire J.
通讯作者：
Booker, Squire J.