Detection and determination of p-coumaroylated units in lignins
Detection and determination of p-coumaroylated units in lignins
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DOI：
10.1021/jf981140j
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发表时间：
1999-05-01
影响因子：
6.1
通讯作者：
Ralph, J
中科院分区：
文献类型：
--
作者：
Lu, FC;Ralph, J
衍生化后再还原裂解？（DFRC）方法裂解木质素中的α-和β-醚，但留下完整的木质素γ-酯。当施用于在其木质素上含有对香豆酸酯的草时，释放出酯化的单月桂醇衍生物。在DFRC过程中，对香豆酸双键发生饱和，因此释放的产物为4-乙酰氧基苯基丙酸4-乙酰氧基肉桂酯。酯的合成允许测定释放产物的响应因子。玉米和竹子木质素释放221和38 μ mol/g的p-香豆酸衍生酯。芥子酯比松柏酯含量高得多。在共轭物中的竹子和玉米木质素的S/G比分别为12和38倍，大于DFRC释放的正常单体，对乙酰基单元的酰化具有很强的选择性的证据。三种可能的生化机制，将p-香豆酸进入木质素，证据是越来越多的过程涉及到正常的木质化过程中的预酰化monolignols纳入。
The derivatization followed by reductive cleavage? (DFRC) method cleaves alpha- and beta-ethers in Lignins but leaves lignin gamma-esters intact. When applied to grasses, which contain p-coumarate esters on their lignins, esterified monolignol derivatives are released. Saturation of the p-coumarate double bond occurs during DFRC, so the released products are 4-acetoxycinnamyl 4-acetoxyphenylpropionates. Synthesis of the esters allowed determination of response factors for the released products. Maize and bamboo Lignins released 221 and 38 mu mol/g of p-coumarate;derived esters. The sinapyl ester was much more abundant than the coniferyl one. The bamboo and maize lignin S/G ratios in the conjugates were 12 and 38 times greater than those of the normal monomers released by DFRC, evidence of a strong selectivity for acylation of syringyl units. Of three possible biochemical mechanisms for incorporating p-coumarates into lignin, evidence is mounting that the process involves incorporation of preacylated monolignols into the normal lignification process.