作者:Paul J. Keller、Quang Le Van、Adelbert Bacher、Heinz G. Floss
DOI:10.1016/s0040-4020(01)88657-9
日期:1983.1
Several recently developed NMR techniques were used to analyze samples of biosynthetically labeled riboflavin tetraacetate. The xylene ring of riboflavin consists of two biogenetically identical halves arising from dismutation of a lumazine precursor. The origin of the four carbons which eventually form this xylene ring eas investigated. Carbon-13 labeled precursors were fed to growing cultures of
几种最近开发的NMR技术用于分析生物合成标记的核黄素四乙酸盐的样品。核黄素的二甲苯环由两个生物上完全相同的半部分组成,这两个半部分是通过先天鲁嗪的歧化而形成的。研究了最终形成该二甲苯环的四个碳的起源。碳13标记的前体被喂入棉铃兰生长的培养物中,分离出产生的核黄素并进行乙酰化。由于存在许多13 C- 13,衍生自[U- 13 C 6 ]葡萄糖的核黄素四乙酸盐样品具有复杂的13 C- NMR光谱。C联轴器和重叠的多重峰。类似于质子实验所进行的13 C-单核-J光谱简化了该材料的光谱分析。可以看到各个13 C多重峰,将数据投影到13 C化学位移轴上会产生13 C NMR光谱,该光谱同时被13 C和1 H宽带解耦(正常的1 H宽带解耦为整个使用)。甲13 C-同核-2D-化学位移相关性光谱用来确定在核糖醇基侧链偶联伴侣。但是,2D-INADEQUATE更适合于确定整个光谱的碳-碳连通性。这三种技术的结合允许进行明确的13
Chemical synthesis of allyl-[13C6]-glucuronate
作者:Bachir Latli、Matt Hrapchak、Ravikumar Seetharama、Dhileepkumar Krishnamurthy、Chris H. Senanayake
C3 Epimerization of Glucose, via Regioselective Oxidation and Reduction
作者:Varsha R. Jumde、Niek N. H. M. Eisink、Martin D. Witte、Adriaan J. Minnaard
DOI:10.1021/acs.joc.6b02074
日期:2016.11.18
Palladium-catalyzedoxidation can single out the secondary hydroxyl group at C3 in glucose, circumventing the more readily accessible hydroxyl at C6 and the more reactive anomeric hydroxyl. Oxidation followed by reduction results in either allose or allitol, each a rare sugar that is important in biotechnology. Also, N-acetylglucosamine is selectively oxidized at C3. These results demonstrate that
Chemoenzymatic synthesis of GM3, Lewis x and sialyl Lewis x oligosaccharides in 13C-enriched form
作者:Mark A. Probert、Mark.J. Milton、Richard Harris、Sergio Schenkman、Jonathan M. Brown、Steven W. Homans、Robert A. Field
DOI:10.1016/s0040-4039(97)01304-x
日期:1997.8
In connection with studies on the solution and protein-bound conformation of oligosaccharides, we had reason to consider the application of C-13-enriched sugars. Herein we describe the synthesis of ganglioside GM(3) trisaccharide (1), Lewis x trisaccharide (2) and the sialyl Lewis x tetrasaccharide (3) from [U-C-13]-D-Glc, [U-C-13]-L-Gal and [U-C-13]-pyruvate. (C) 1997 Elsevier Science Ltd.
Rapid Preparation of Isotopolog Libraries by in Vivo Transformation of <sup>13</sup>C-Glucose. Studies on 6,7-Dimethyl-8-ribityllumazine, a Biosynthetic Precursor of Vitamin B<sub>2</sub>
An Escherichia coli strain engineered for expression of the ribABGH genes of Bacillus subtilis was shown to produce 100 mg of the riboflavin precursor 6,7-dimethyl-8-ribityllumazine per liter of minimal medium. Growth of the recombinant strain in medium supplemented with [U-C-13(6)]glucose and/or (NH4Cl)-N-15 as single sources of carbon and/or nitrogen afforded 6,7-dimethyl-8-ribityllumazine universally labeled with C-13 and/or N-15. The yield of [U-C-13(13)]-6,7-dimethyl-8-ribityllumazine based on [U-C-13(6)]glucose was 25 mg/g. Fermentation with [1-C-13(1)]-, [2-C-13,]-, or [3-C-13(1)]glucose afforded mixtures of 6,7-dimethyl-8-ribityllumazine isotopologs, predominantly with C-13 enrichment of single carbon atoms. The isotope-labeled samples enabled a comprehensive NMR analysis of 6,7-dimethyl-8-ribityllumazine. Isotopolog libraries of a wide variety of microbial metabolites can be produced by the same experimental approach.