使用7%KOH,多糖PAK已从挪威云杉的针叶树中分离出来。发现PAK主要含有阿拉伯葡糖醛酸木聚糖,木葡聚糖和阿拉伯聚糖,还有果胶多糖,葡甘露聚糖和阿拉伯半乳聚糖蛋白(AGP),如通过1D/2DNMR分析确定的。发现PAK在DEAE-纤维素上的分馏导致果胶的同时洗脱,阿拉伯葡糖醛酸聚糖和AGP。很明显,4-OMe-α-D-GlcpA和木糖的含量,1,4-β-D-GlcpA,T-β-D-GlcpA随NaCl浓度的增加而增加。然而,1,4-α-D-GalpA含量几乎与NaCl浓度无关,表明果胶多糖浓度不变。有趣的是,用0.1-0.3MNaCl溶液提取的果胶比用水和0.01MNaCl提取的果胶更富含鼠李糖半乳糖醛酸-I(RG-I)。结论:RG-I的含量,AGP和阿拉伯葡糖醛酸随NaCl浓度的升高而升高。强烈的信号表明木聚糖和RG-I结构域之间的分子间连接,即阿拉伯葡糖醛酸木聚糖的一部分与RG-I共价结合,在获得的多糖的HMBC光谱中观察到。在此发现鼠李糖半乳糖醛酸I和木聚糖之间的新关系与流行的细胞壁模型相矛盾。
Using 7 % KOH, the polysaccharide PAK has been isolated from the coniferous greens of Norway spruce. PAK was found to contain predominantly arabinoglucuronoxylan, xyloglucan and arabinan, but also pectic polysaccharides, glucomannan and arabinogalactan proteins (AGPs), as determined by 1D/2D NMR analysis. It was found that fractionation of PAK on DEAE-cellulose resulted in simultaneous elution of pectins, arabinoglucuronoxylans and AGPs. It was evident that the content of 4-OMe-α-D-GlcpA and xylose, 1,4-β-D-GlcpA, and T-β-D-GlcpA increased with an increase in NaCl concentration. However, 1,4-α-D-GalpA content was almost independent of NaCl concentration, indicating unchanged pectic polysaccharide concentration. Interestingly, pectins extracted with 0.1-0.3 M NaCl solutions were richer in rhamnogalacturonan-I (RG-I) than those extracted with water and 0.01 M NaCl. Conclusion: The content of RG-I, AGPs and arabinoglucuronoxylan rises with rising NaCl concentration. An intense signal indicating an intermolecular linkage between the xylan and RG-I domains, i.e. that part of the arabinoglucuronoxylan is covalently bound to RG-I, is observed in the HMBC spectra of the polysaccharides obtained. The discovery here of a new relationship between rhamnogalacturonan I and xylan contradicts the prevailing cell wall model.