Research Group of Traditional Food, Korea Food Research Institute, Wanju 55365, Republic of Korea.
Research Group of Healthcare, Korea Food Research Institute, Wanju 55365, Republic of Korea; Department of Food Science and Biotechnology, College of BioNano Technology, Gachon University, Seongnam 13120, Republic of Korea.
Enzyme Microb Technol. 2020 Apr;135:109505. doi: 10.1016/j.enzmictec.2019.109505. Epub 2019 Dec 27.
Amylosucrase (ASase) has great industrial potential owing to its multifunctional activities, including transglucosylation, polymerization, and isomerization. In the present study, the properties of Deinococcus geothermalis ASase (DGAS) expressed in Corynebacterium glutamicum (cDGAS) and purified via Ni-NTA affinity chromatography were compared to those of DGAS expressed in Escherichia coli (eDGAS). The pH profile of cDGAS was similar to that of eDGAS, whereas the temperature profile of cDGAS was lower than that of eDGAS. The melting temperature of both enzymes did not differ significantly. Interestingly, polymerization activity was slightly lower in cDGAS than in eDGAS, whereas luteolin (an acceptor molecule) transglucosylation activity in cDGAS was 10 % higher than that in eDGAS. Analysis of protein secondary structure via circular dichroism spectroscopy revealed that cDGAS had a lower strand/helix ratio than eDGAS. The present results indicate that cDGAS is of greater industrial significance than eDGAS.
淀粉蔗糖酶（ASase）具有转葡糖苷、聚合和异构化等多种功能，具有巨大的工业潜力。在本研究中，比较了在谷氨酸棒杆菌中表达并通过 Ni-NTA 亲和层析纯化的地热能球菌淀粉蔗糖酶（DGAS）（cDGAS）和在大肠杆菌中表达的 DGAS（eDGAS）的性质。cDGAS 的 pH 曲线与 eDGAS 的相似，而 cDGAS 的温度曲线低于 eDGAS。两种酶的熔点没有显著差异。有趣的是，聚合活性在 cDGAS 中略低于 eDGAS，而 cDGAS 中木犀草素（受体分子）的转葡糖苷活性比 eDGAS 高 10%。通过圆二色性光谱分析蛋白质二级结构表明，cDGAS 的链/螺旋比低于 eDGAS。本研究结果表明，cDGAS 比 eDGAS 具有更大的工业意义。
