College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Analytical Chemistry for Biology and Medicine, Wuhan University, Ministry of Education, China.
Int J Biol Macromol. 2019 Feb 15;123:269-279. doi: 10.1016/j.ijbiomac.2018.11.020. Epub 2018 Nov 6.
Pure yeast β‑glucan (YG1) was obtained by drying and defatting the crude β‑glucan from Saccharomyces cerevisiae. The YG1 structure was characterized by total sugar content, protein content, FT-IR spectroscopy and monosaccharide composition analysis. Different molecular weight fractions of water-soluble yeast β‑glucan (WYG) were prepared by extraction with 2.0 M NaOH, degradation of the insoluble residue with 1.0 M HCl based on single-factor experiments, and fractionation on a size exclusion chromatography column (SEC, Sephacryl S-400). The molecular sizes of as-obtained fractions were measured by multi-angle laser light scattering combined with SEC and differential refractive index detector (SEC-MALLS-RI). Results indicated that YG1 had a high purity and was almost composed of β‑d‑glucose (97.71%) except trace mannose. The WYG yields by alkali extraction and acidolysis were 12.41% and 42.85%, respectively. Fourteen fractions with molecular weight (M) from 4590 to 31.61 kDa and low polydispersity index (M/M of ~1) were successfully separated, showing high recovery rates of 61.9-92.5%. Additionally, these fractions could promote the proliferation of RAW264.7 macrophages, and the fraction (M = 2496 kDa) exhibited the highest cell viability of 145.8 ± 4.3% at a low concentration of 1.56 μg/mL. This work not only provides an efficient method for separating WYG fractions with different molecular weights and low polydispersity, but also lays a theoretical basis for interpreting the relationship between molecular size and bioactivity.
从酿酒酵母中提取得到粗β-葡聚糖，经过干燥和脱脂处理得到纯酵母β-葡聚糖（YG1）。通过总糖含量、蛋白质含量、傅里叶变换红外光谱（FT-IR）和单糖组成分析对 YG1 结构进行了表征。通过单因素实验，用 2.0 M NaOH 提取、用 1.0 M HCl 降解不溶性残渣，制备得到不同分子量的水溶性酵母β-葡聚糖（WYG）。用尺寸排阻色谱柱（SEC，Sephacryl S-400）对得到的级分进行分离。用多角度激光光散射结合 SEC 和差示折射率检测器（SEC-MALLS-RI）测量获得级分的分子量。结果表明，YG1 纯度较高，除痕量甘露糖外，几乎由β-d-葡萄糖（97.71%）组成。碱提取和酸解的 WYG 产率分别为 12.41%和 42.85%。成功分离出 14 个分子量（M）从 4590 到 31.61 kDa 且低多分散指数（M/M 约为 1）的级分，回收率高达 61.9-92.5%。此外，这些级分可以促进 RAW264.7 巨噬细胞的增殖，在低浓度 1.56 μg/mL 时，分子量（M=2496 kDa）的级分表现出最高的细胞活力 145.8±4.3%。这项工作不仅提供了一种有效分离不同分子量和低多分散性 WYG 级分的方法，而且为解释分子量与生物活性之间的关系奠定了理论基础。
