Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4J1 Canada.
Plant Physiol. 1979 Mar;63(3):557-61. doi: 10.1104/pp.63.3.557.
Hydroxyproline-poor glycoprotein contains a single polypeptide chain with lysine at the N-terminus. Removal of carbohydrate attached to serine by alkali treatment produces two polypeptide fractions. Labeling with (35)S indicates that most serine residues having a carbohydrate substituent removed by alkali occur on the polypeptide fraction of lower molecular weight. Following alkali treatment, two additional N-terminal amino acids, proline and glycine, were detected suggesting that alkali treatment also cleaves peptide bonds. Methylation analysis of native and degraded glycoproteins, extracted 24, 27, and 36 hours after wounding, demonstrates the following structural features of carbohydrate attached to serine. Arabinose may be (1 --> 2)-, (1 --> 3)-, or (1 --> 5)-linked, glucose occurs as a chain of beta-(1 --> 4)-linked residues, and galactose occurs as a nonreducing terminal unit.
羟脯氨酸缺乏糖蛋白含有单一的多肽链,其 N 末端为赖氨酸。用碱处理去除丝氨酸上连接的碳水化合物会产生两个多肽片段。用 (35)S 标记表明,通过碱处理去除碳水化合物取代基的大多数丝氨酸残基位于分子量较低的多肽片段上。碱处理后,检测到另外两个 N 末端氨基酸,脯氨酸和甘氨酸,表明碱处理还会切断肽键。对损伤后 24、27 和 36 小时提取的天然和降解糖蛋白进行甲基化分析,证明了与丝氨酸结合的碳水化合物的以下结构特征。阿拉伯糖可能是 (1 --> 2)-、(1 --> 3)- 或 (1 --> 5)- 连接的,葡萄糖作为β-(1 --> 4)-连接残基的链存在,而半乳糖作为非还原末端单元存在。