摘要
采用水提醇沉法从南瓜粉中提取南瓜糖蛋白,分别用硫酸铵、乙醇分级沉淀及琼脂糖凝胶电泳法对南瓜糖蛋白进行分离纯化,定性检测后用碱性β-消除反应及核磁共振氢谱(Proton Nuclear Magnetic Resonance,~1H NMR)、核磁共振碳谱(Carbon 13Nuclear Magnetic Resonance,^(13)C NMR)技术测定糖肽键的结构。结果显示:纯化后的糖蛋白不含游离还原糖和淀粉,其在紫外240 nm附近南瓜糖蛋白碱水解液吸光度值发生了明显的变化,证明南瓜糖蛋白的糖肽键主要为O-糖肽键;其多糖的~1H NMR和^(13)C NMR谱图表明,该多糖组分的单糖残基中包含α-和β-两种糖苷键类型,且南瓜多糖主要含有3种端基碳分别为→4)-α-D-半乳糖-(1→、T-α-D-半乳糖-(1→和→2)-α-L-鼠李糖-(1→,在175.57和171.25处的共振吸收峰说明多糖中含有糖醛酸和脂类结构。
Pumpkin glycoproteins were extracted from pumpkin powder with water extraction and alcohol precipitation. The pumpkin glycoproteins were separated and purified in sequence with ammonium sulfate and ethanol precipitation and agarose gel electrophoresis. After qualitative investigation and alkaline β-elimination reaction,-1H NMR and -（13）C NMR were adopted to measure the structure of glycopeptide linkage. The experiments showed that：the purified glycoprotein did not contain the free reducing sugar and starch. In the spectrum near UV 240 nm,there was a significant change in the absorbance of the hydrolysate of the pumpkin glycoprotein,which proved that the glycopeptide linkage was mainly O-glycopeptide. Meanwhile,the -1H NMR and -（13）C NMR spectrogram of its polysaccharide showed that the monosaccharide residue of the polysaccharide contained bothα-and β-glycoside bond types,while polysaccharides mainly contained three anomeric carbon which were→4）-α-D-Galp A-（1→,T-α-D-Galp-（1→ and→2）-α-L-Rhap-（1→,at175.57 and 171.25,the resonance-absorption peak indicates the polysaccharides contains uronic acid and lipid structure.
出处
《食品研究与开发》
CAS
北大核心
2017年第16期61-65,共5页
Food Research and Development
关键词
南瓜
糖蛋白
琼脂糖凝胶电泳
核磁共振
pumpkin
glycoprotein
agarose gel electrophoresis
nuclear magnetic resonance（NMR）
