新颖的特定位置的18O / 16O碳水化合物测量方法。二。C4起源淀粉中葡萄糖单元的完整分子内18O / 16O谱图。,Analytical Chemistry

当前位置： X-MOL 学术 › Anal. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

新颖的特定位置的18O / 16O碳水化合物测量方法。二。C4起源淀粉中葡萄糖单元的完整分子内18O / 16O谱图。
Analytical Chemistry ( IF 6.7 ) Pub Date : 2020-05-04 , DOI: 10.1021/acs.analchem.9b05314
Ran Ma ₁ , Yu Zhao ₁ , Lan Liu _{1,

2} , Zhenyu Zhu ₁ , Bo Wang ₁ , Ying Wang ₁ , Xijie Yin ₃ , Jing Su ₃ , Youping Zhou _{1,

2}

Affiliation

有关植物光合碳同化，生理学和生物化学的信息被锁定在高级植物碳水化合物的各个位置的¹⁸ O / ¹⁶ O比值中，但由于难以进行这些测定而未被充分利用。我们报告的湿化学方法的扩展我们用来访问¹⁸ O / ¹⁶具有新颖GC /热解/基于IRMS法O-3的葡萄糖的O比，以确定¹⁸ O / ¹⁶ O -的O比4，O-5和O-6。葡萄糖的1、2、5和6位上的O原子（OH基）通过丙酮化保护（转化为1,2; 5,6-di- O-异亚丙基-葡萄糖呋喃糖，DAGF）。然后将DAGF转化为6-溴-6-脱氧-1,2; 3,5-二-O-异亚丙基-葡糖呋喃糖（6-bromoDAGF），同时用N-溴代琥珀酰亚胺和三苯基膦除去O-6 。在NaH的催化下，DAGF还在CH ₃ I下在O-3处甲基化成3-甲基DAGF，然后将其脱丙酮成1，2 - O-异亚丙基-3- O-甲基-葡糖呋喃糖（3-甲基MAGF）。然后在Ph ₃ P和咪唑的催化下，通过I ₂氧化从3-甲基MAGF中整体除去O-5和O-6 。然后应用同位素质量平衡计算¹⁸ O / ¹⁶O-5和O-6整体的O分别为O-6。在底物转化为产物的不同阶段取样并施加瑞利型分馏模型中使用，当基片的定量转化率是无法实现的，计算δ ¹⁸转换后的基板的O-。葡萄糖与苯肼于phenylglucosazone的定量转化也允许的δ的计算¹⁸ Ò ₂通过施加在两者之间同位素质量平衡。甲C4淀粉衍生的葡萄糖分子内δ ¹⁸ O配置文件现在确定：O-3相对富集的（由12.16 MUR），O-4相对耗尽（通过20.40-31.11 MUR），和O-2被轻微富集的（由2.40 mUr）。

"点击查看英文标题和摘要"

Novel Position-Specific 18O/16O Measurement of Carbohydrates. II. The Complete Intramolecular 18O/16O Profile of the Glucose Unit in a Starch of C4 Origin.

Information about plant photosynthetic carbon assimilation, physiology, and biochemistry is locked in the ¹⁸O/¹⁶O ratios of the individual positions of higher plants carbohydrates but is under-utilized, because of the difficulty of making these determinations. We report the extension of the wet chemistry approach we used to access the ¹⁸O/¹⁶O ratio of O-3 of glucose with a novel GC/Pyrolysis/IRMS-based method, to determine the ¹⁸O/¹⁶O ratios of O-4, O-5, and O-6. The O atoms (OH groups) at positions 1, 2, 5, and 6 of glucose were protected by acetonation (converting to 1,2;5,6-di-O-isopropylidene-glucofuranose, DAGF). The DAGF was then converted to 6-bromo-6-deoxy-1,2;3,5-di-O-isopropylidene-glucofuranose (6-bromoDAGF) with the simultaneous removal of O-6 with N-bromosuccinimide and triphenylphosphine. The DAGF was also methylated at O-3 with CH₃I under the catalysis of NaH to 3-methylDAGF, which was then deacetonated to 1,2-O-isopropylidene-3-O-methyl-glucofuranose (3-methylMAGF). O-5 and O-6 were then removed as a whole from 3-methylMAGF by I₂ oxidization under the catalysis of Ph₃P and imidazole. Isotope mass balance was then applied to calculate the ¹⁸O/¹⁶O of O-5 and O-6 as a whole and O-6, respectively. Sampling at different stages of substrate conversion to product and applying a Rayleigh-type fractionation model were employed, when quantitative conversion of substrate was unachievable to calculate the δ¹⁸O of the converted substrate. Quantitative conversion of glucose with phenylhydrazine to phenylglucosazone also allowed for the calculation of δ¹⁸O₂ by applying isotope mass balance between the two. A C4 starch-derived glucose intramolecular δ¹⁸O profile is now determined: O-3 is relatively enriched (by 12.16 mUr), O-4 is relatively depleted (by 20.40–31.11 mUr), and O-2 is marginally enriched (by 2.40 mUr) against the molecular average.

更新日期：2020-05-04

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南