Jeong Da-Woon, Jeong Hyun-Mo, Shin Yu-Jeong, Woo Seung-Hye, Shim Jae-Hoon
Department of Food Science and Nutrition, and The Korean Institute of Nutrition, Hallym University, Chuncheon, 24252 Republic of Korea.
Food Sci Biotechnol. 2019 Dec 23;29(5):667-674. doi: 10.1007/s10068-019-00707-4. eCollection 2020 May.
To determine the physiochemical properties of the 4-α-glucanotransferase from sp., the _0114 gene encoding 4-α-glucanotransferase was cloned from subsp. JCM 1217 and expressed in . The amino acid sequence alignment indicated that the recombinant protein, named BL-αGTase, belongs to the glycoside hydrolase (GH) family 77. BL-αGTase was purified using nickel-nitrilotriacetic acid affinity chromatography and characterized using various substrates. The enzyme catalyzed the disproportionation activity, which transfers a glucosyl unit from oligosaccharides to acceptor molecules, and had the highest activity at 40 °C and pH 6.0. In the presence of 5 mM metal ions, in particular Cu, Zn, and Fe, BL-αGTase activity was reduced. To determine whether BL-αGTase can be used to generate thermoreversible gels, potato starch was treated with BL-αGTase for various reaction times. The BL-αGTase-treated starches showed sol-gel reversibility and melted at 59.6-75.7 °C.
为了确定来自某菌的4-α-葡聚糖转移酶的理化性质，从嗜热栖热放线菌亚种JCM 1217中克隆了编码4-α-葡聚糖转移酶的_0114基因，并在大肠杆菌中进行表达。氨基酸序列比对表明，重组蛋白命名为BL-αGTase，属于糖苷水解酶（GH）家族77。使用镍-次氮基三乙酸亲和色谱法对BL-αGTase进行纯化，并使用各种底物对其进行表征。该酶催化歧化活性，即将寡糖中的一个葡萄糖基单元转移到受体分子上，在40°C和pH 6.0时具有最高活性。在存在5 mM金属离子，特别是铜、锌和铁的情况下，BL-αGTase的活性降低。为了确定BL-αGTase是否可用于生成热可逆凝胶，用BL-αGTase处理马铃薯淀粉不同反应时间。经BL-αGTase处理的淀粉表现出溶胶-凝胶可逆性，在59.6-75.7°C时熔化。
