Cumming Carol M, Rizkallah Hind D, McKendrick Kimberley A, Abdel-Massih Roula M, Baydoun Elias A-H, Brett Christopher T
Institute of Biomedical and Life Sciences, Plant Science Group, Glasgow University, Bower Building, Glasgow, G12 8QQ, UK.
Planta. 2005 Oct;222(3):546-55. doi: 10.1007/s00425-005-1560-2. Epub 2005 May 24.
Golgi-enriched enzyme preparations prepared from etiolated pea epicotyls incorporated [U-(14)C]galactose from UDP-[U-(14)C]galactose into the 1,4-beta-galactan sidechains of a pectin-xyloglucan complex. This complex could bind to paper and was degraded both by pectin-degrading enzymes and by a xyloglucan-specific endoglucanase. Gel permeation chromatography was used to assess the molecular size of the complex and of enzymically-degraded, galactan-containing fragments of it. Etiolated pea stems were labelled with [U-(14)C]sucrose for 1 h, and the newly-synthesised cell wall polysaccharides were extracted with EDTA or NaOH and fractionated by ion-exchange chromatography. The NaOH-extracted, acidic radioactive polysaccharides obtained in this way were also degraded both by pectin-degrading enzymes and by xyloglucan-specific endoglucanase. Analysis of the radioactive sugar composition indicated that neutral sugars characteristic of both pectin and xyloglucan were present. Analysis of the total non-radioactive, neutral sugar composition of the NaOH-extracted, acidic cell-wall polysaccharides indicated that pectin-xyloglucan complexes were a general feature of the cell wall in this tissue.
从黄化豌豆上胚轴制备的富含高尔基体的酶制剂，将UDP-[U-(14)C]半乳糖中的[U-(14)C]半乳糖掺入到果胶-木葡聚糖复合物的1,4-β-半乳聚糖侧链中。这种复合物能与纸张结合，并且能被果胶降解酶和木葡聚糖特异性内切葡聚糖酶降解。凝胶渗透色谱法用于评估该复合物及其酶解后的含半乳聚糖片段的分子大小。用[U-(14)C]蔗糖标记黄化豌豆茎1小时，然后用EDTA或NaOH提取新合成的细胞壁多糖，并通过离子交换色谱法进行分级分离。以这种方式获得的NaOH提取的酸性放射性多糖，同样能被果胶降解酶和木葡聚糖特异性内切葡聚糖酶降解。放射性糖成分分析表明，果胶和木葡聚糖特有的中性糖都存在。对NaOH提取的酸性细胞壁多糖的总非放射性中性糖成分分析表明，果胶-木葡聚糖复合物是该组织细胞壁的一个普遍特征。
