小麦胚水溶性糖蛋白(WGWSGP)的化学组成及结构分析

The Studies on Chemical Compositions and Structure of Wheat GermWater-Soluble Glycoprotein (WGWSGP)

为研究小麦胚水溶性糖蛋白(WGWSGP)的化学组成和结构,采用化学比色法、氨基酸自动分析和气相色谱等方法分别对其蛋白质和糖的含量和组成进行了检测;并通过β-消去、紫外扫描、红外光谱和核磁共振等对其结构进行了初步分析。分析结果表明:WGWSGP中糖的含量高达43.6%,并且甘露糖是主要中性糖组分,其含量占中性糖总量的94%;WGWSGP含有多种人体所必需的氨基酸,其中天冬氨酸、谷氨酸、甘氨酸、缬氨酸的含量较高,不含蛋氨酸。WGWSGP中糖与蛋白的肽链之间的连接点类型是O-糖肽键;聚糖是以α糖苷键相连,寡糖链的糖苷键构型为α型吡喃糖;寡糖链的α-D-甘露糖吡喃糖残基上的C-2、C-3位或C-4位羟基没有发生取代;样品中含有己糖醛酸和6-位脱氧糖的甲基存在。

To study on chemical compositions and structure of WGWSGP, the contents and compositions of protein and sugarin WGWSGP was determined by colorimetric assay, amino acid composition analyzer and gas chromatography, respectively; andits structure was preliminarily studied by β-elimination, UV scan, IR and NMR spectrums. The results showed that total carbo-hydrate content of WGWSGP was up to 43.6%, and mannose was the main neutral monosaccharide. WGWSGP contained manykinds of essential amino acids, of which the contents of Asp, Glu, Gly and Val were higher, but Met was absent. The linkage betweenthe glycan and protein was O-linkage and the glycans of WGWSGP were linked with α-glucosidic bonds. Furthermore theconfiguration of the glucosidic bonds was α-pyranose; hydroxy groups in C-2, C-3 or C-4 of α-D-mannopyranose residueswere not substituted. Hexuronic acids and the methyls of 6-desose occurred in WGWSGP.