School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1 Hatatate, Taihaku-ku, Sendai, Miyagi, Japan.
J Food Sci. 2020 Aug;85(8):2498-2505. doi: 10.1111/1750-3841.15315. Epub 2020 Jul 6.
Miso, a fermented paste made from soybeans, is used traditionally for seasoning of food. It has been a protein and nitrogen source since ancient times in Japan because of its high nutritional value. Furthermore, it has important health functions such as the estrogen-like activity of isoflavones, anti-oxidation, and angiotensin-converting-enzyme inhibition activity. Moreover, it has activity for neutralization of lipopolysaccharide (LPS) from Escherichia coli. Nevertheless, the mechanisms of that activity remain unclear. For this study, we purified and identified the proteins responsible for LPS-neutralization. After proteins were isolated from a miso extract using Blue native polyacrylamide gel electrophoresis, a protein found at 10 to 30 kDa on the polyacrylamide gel was identified using nano LC-MS/MS as 2S albumin in soybean (Glycine max). The protein had two LPS binding motifs: SKWQHQ (22 amino acid residues) and EKQKKKMEKE (131 amino acid residues). The protein in miso was found to have LPS neutralization activity, as assayed by prostaglandin D (PGD ) production from macrophage cells. The PGD production by macrophage cells was inhibited by LPS-neutralizing protein (LNP) from miso. Particularly, 50 mg/mL of LNP solution and LPS (10 µg/mL) inhibited production of PGD from the cells. The data were inferred as significantly different (P < 0.05) from statistical analyses by analysis of variance testing and Tukey tests. The 2S albumin in soybean is LNP, an LPS-neutralizing protein, produced in miso. PRACTICAL APPLICATION: A protein from miso fermented soy paste neutralizes an Escherichia coli intestinal bacterial product, lipopolysaccharide (LPS), which causes intestinal inflammation. Miso and its protein are anticipated for use as a probiotic agent to prevent intestinal inflammation in humans and domestic animals. Miso is useful not only as a seasoning for food, but also as a health-functional food because it is an LPS-neutralizing agent.
味噌是一种由大豆制成的发酵糊状物，传统上用于调味食物。自古以来，它因其高营养价值而一直是日本的蛋白质和氮源。此外，它还具有重要的健康功能，如异黄酮的类雌激素活性、抗氧化作用和血管紧张素转化酶抑制活性。而且，它还具有中和大肠杆菌脂多糖（LPS）的活性。然而，其作用机制尚不清楚。在这项研究中，我们纯化并鉴定了负责 LPS 中和的蛋白质。从味噌提取物中使用 Blue native 聚丙烯酰胺凝胶电泳分离蛋白质后，在聚丙烯酰胺凝胶上发现的 10 至 30 kDa 的蛋白质使用纳升 LC-MS/MS 鉴定为大豆中的 2S 白蛋白（Glycine max）。该蛋白质具有两个 LPS 结合基序：SKWQHQ（22 个氨基酸残基）和 EKQKKKMEKE（131 个氨基酸残基）。通过检测巨噬细胞细胞产生的前列腺素 D（PGD）来测定味噌中的蛋白质具有 LPS 中和活性。味噌中的 LPS 中和蛋白（LNP）抑制了巨噬细胞细胞中 PGD 的产生。特别是，50 mg/mL 的 LNP 溶液和 LPS（10 µg/mL）抑制了细胞中 PGD 的产生。通过方差分析检验和 Tukey 检验进行的统计分析推断数据存在显著差异（P < 0.05）。大豆中的 2S 白蛋白是 LNP，一种在味噌中产生的 LPS 中和蛋白。从发酵大豆糊状物中提取的蛋白质可以中和大肠杆菌肠道细菌产物脂多糖（LPS），LPS 会引起肠道炎症。味噌及其蛋白质有望作为益生菌制剂，预防人类和家畜的肠道炎症。味噌不仅可作为食物的调味料，而且由于它是 LPS 中和剂，因此还是一种具有健康功能的食品。
