School of Biotechnology and Food Engineering, Hefei University of Technology, No. 193 Tunxi Road, Hefei 230009, People's Republic of China.
Int J Biol Macromol. 2013 Oct;61:439-47. doi: 10.1016/j.ijbiomac.2013.08.008. Epub 2013 Aug 22.
The aim of this study was to investigate the inhibitory effects of molecular weight alteration of Dendrobium huoshanense polysaccharide on protein nonenzymatic glycation. For this purpose, one homogeneous active polysaccharide DHPD1 with molecular weight 3.2 kDa was extracted from D. huoshanense. GC analysis showed that DHPD1 was mainly composed of glucose, arabinose, galactose in a molar ratio of 0.023:1.023:0.021 with a trace of mannose and xylose. In order to get DHPD1-derived fragments with different molecular weight, response surface methodology was employed to optimize the enzymatic degradation conditions. The maximum reducing sugar production (0.399 mg/mL) was obtained under an optimal condition including pectinase dosage 126 U/mL, reaction pH 4.46 and reaction temperature 48 °C. By applying this condition, three DHPD1-derived fragments with different molecular weights were obtained through changing the hydrolysis time. Infrared spectroscopy analysis indicated that the backbone structure of DHPD1 was not destroyed by pectinase hydrolysis. Monosaccharide composition analysis showed that pectinase preferred to liberate glucose from DHPD1. The inhibitory action of DHPD1 on protein nonenzymatic glycation reduced with the decrease of molecular weight.
本研究旨在探讨霍山石斛多糖分子量改变对蛋白质非酶糖基化的抑制作用。为此，从霍山石斛中提取出一种均一的活性多糖 DHPD1，其分子量为 3.2 kDa。GC 分析表明，DHPD1 主要由葡萄糖、阿拉伯糖、半乳糖组成，摩尔比为 0.023:1.023:0.021，同时还含有少量的甘露糖和木糖。为了得到具有不同分子量的 DHPD1 衍生片段，采用响应面法优化了酶解条件。在果胶酶用量 126 U/mL、反应 pH 4.46 和反应温度 48°C 的最佳条件下，获得了最大还原糖产量（0.399 mg/mL）。通过改变水解时间，应用该条件得到了三种具有不同分子量的 DHPD1 衍生片段。红外光谱分析表明，果胶酶水解并未破坏 DHPD1 的骨架结构。单糖组成分析表明，果胶酶更倾向于从 DHPD1 中释放葡萄糖。DHPD1 对蛋白质非酶糖基化的抑制作用随分子量的降低而降低。
