Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS , Université Paris-Saclay , 78000 Versailles , France.
Department of Biochemistry, and The Department of Energy's Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute , University of Wisconsin , Madison , Wisconsin 53726 , United States.
J Agric Food Chem. 2018 May 30;66(21):5418-5424. doi: 10.1021/acs.jafc.8b01618. Epub 2018 May 18.
The arabinosyl side chains of grass arabinoxylans are partially acylated by p-coumarate ( pCA) and ferulate (FA). These aromatic side chains can cross-couple wall polymers resulting in modulation of cell wall physical properties. The determination of p-coumaroylated and feruloylated arabinose units has been the target of analytical efforts with trifluoroacetic acid hydrolysis the standard method to release feruloylated and p-coumaroylated arabinose units from arabinoxylans. Herein, we report on a more robust method to measure these acylated units. Acidolysis of extractive-free grass samples in a dioxane/methanol/aqueous 2 M HCl mixture provided the methyl 5- O- p-coumaroyl- and 5- O-feruloyl-l-arabinofuranoside anomers ( pCA-MeAra and FA-MeAra). These conjugates were readily analyzed by liquid chromatography combined with both UV and MS detection. The method revealed the variability of the relative acylation of arabinose units by pCA or FA in grass cell walls. This methodology will permit delineation of hydroxycinnamate acylation patterns in arabinoxylans.
草阿拉伯木聚糖的阿拉伯糖基侧链部分被对香豆酸（pCA）和阿魏酸（FA）酰化。这些芳基侧链可以交叉偶联壁聚合物，从而调节细胞壁的物理性质。对香豆酰化和阿魏酰化阿拉伯糖单位的测定一直是分析努力的目标，三氟乙酸水解是从阿拉伯木聚糖中释放阿魏酰化和对香豆酰化阿拉伯糖单位的标准方法。在此，我们报告了一种更强大的测量这些酰化单位的方法。在二恶烷/甲醇/ 2 M HCl 水溶液混合物中对无提取剂的草样品进行酸解，提供了甲基 5-O-对香豆酰基和 5-O-阿魏酰基-L-阿拉伯呋喃糖苷异构体（pCA-MeAra 和 FA-MeAra）。这些缀合物可通过液相色谱法与紫外和质谱检测法轻松分析。该方法揭示了草细胞壁中 pCA 或 FA 对阿拉伯糖单位相对酰化的可变性。这种方法将允许描绘阿拉伯木聚糖中羟基肉桂酸的酰化模式。
