Cross-linking of maize walls by ferulate dimerization and incorporation into lignin
Cross-linking of maize walls by ferulate dimerization and incorporation into lignin
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DOI：
10.1021/jf0006978
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发表时间：
2000-12-01
影响因子：
6.1
通讯作者：
Hatfield, RD
中科院分区：
文献类型：
--
作者：
Grabber, JH;Ralph, J;Hatfield, RD
用2%阿魏酸酯和阿魏酸乙酯对原玉米壁进行酰基化，研究了阿魏酸酯对木聚糖和木质素的交联作用。过氧化物酶介导的阿魏酸壁和阿魏酸乙酯偶联主要产生8偶联产物，包括3种新的脱氢二聚体。大量的5-5偶联散形仅在壁内形成，表明基质效应影响二聚体的形成。超过60%的阿魏酸壁在H2O2的作用下二聚，这表明木聚糖阿魏酸基化在壁生物合成过程中受到高度调节，从而允许在木质素化开始时广泛形成二聚体。在木质素化过程中，阿魏酸酯和5-5偶联的散列酯比8-5-、8-O-4-和8-8偶联的散列酯与松柏醇的共聚速度更快，形成的醚连接结构更少。大多数阿魏酸盐和阿魏酸盐与木质素结合的可能性超过90%。结果，木聚糖通过阿魏酸二聚化和与木质素结合而广泛交联，但只有一小部分可变的交联可以通过溶解木质素壁来测量。
Cross-linking of xylans and lignin by ferulates was investigated with primary maize walls acylated with 2% ferulate and with ferulate ethyl esters. Peroxidase-mediated coupling of wall ferulate and ethyl ferulate yielded mostly 8-coupled products, including three new dehydrodimers. Significant quantities of 5-5-coupled diferulate formed only within walls, suggesting that matrix effects influence dimer formation. Over 60% of wall ferulate dimerized upon H2O2 addition, suggesting that xylan feruloylation is highly regulated during wall biosynthesis to permit extensive dimer formation at the onset of lignification. During lignification, ferulate and 5-5-coupled diferulate copolymerized more rapidly and formed fewer ether-linked structures with coniferyl alcohol than 8-5-, 8-O-4-, and 8-8-coupled diferulates. The potential incorporation of most ferulates and diferulates into lignin exceeded 90%. As a result, xylans become extensively cross-linked by ferulate dimerization and incorporation to lignin, but only a small and variable proportion of these cross-links is measurable by solvolysis of lignified walls.