Jang Ki-Hyo, Ryu Eun-Ja, Park Buem-Seek, Song Ki-Bang, Kang Soon Ah, Kim Chul Ho, Uhm Tai-Boong, Park Yong-Il, Rhee Sang-Ki
Graduate School of East-West Medical Science, Kyung Hee University, Suwon 449-701, Korea.
J Agric Food Chem. 2003 Apr 23;51(9):2632-6. doi: 10.1021/jf026207o.
A new levan fructotransferase (LFTase) isolated from Arthrobacter oxydans J17-21 was characterized for the production of difructose dianhydride IV (DFA IV). LFTase was purified to apparent homogeneity by Q-Sepharose ion exchange chromatography, Mono-Q HR 5/5 column chromatography, and gel permeation chromatography. The enzyme had an apparent molecular mass of 54000 Da. The optimum pH for the enzyme-catalyzed reaction was pH 6.5, and the optimum temperature was observed at 45 degrees C. The LFTase was activated by the presence of CaCl(2) and EDTA-2Na but inhibited strongly by MnCl(2) and CuSO(4) at 1 mM and completely by FeSO(4) and Ag(2)SO(4) at 1 mM. A bacterial levan from Zymomonas mobilis was incubated with an LFTase; final conversion yield from the levan to DFA IV was 35%. Neither inulin, levanbiose, sucrose, dextran, nor starch was hydrolyzed by LFTase. DFA IV was very stable at acidic pH and high temperature, thus indicating that DFA IV may be suitable for the food industry and related areas.
从氧化节杆菌J17 - 21中分离出的一种新型果聚糖转移酶（LFTase）被用于研究二果糖酐IV（DFA IV）的生产特性。通过Q - Sepharose离子交换色谱、Mono - Q HR 5/5柱色谱和凝胶渗透色谱将LFTase纯化至表观均一。该酶的表观分子量为54000 Da。酶催化反应的最适pH为6.5，最适温度为45℃。LFTase在CaCl₂和EDTA - 2Na存在下被激活，但在1 mM时被MnCl₂和CuSO₄强烈抑制，在1 mM时被FeSO₄和Ag₂SO₄完全抑制。将运动发酵单胞菌的细菌果聚糖与LFTase一起孵育；从果聚糖到DFA IV的最终转化率为35%。LFTase不水解菊粉、果聚糖二糖、蔗糖、葡聚糖和淀粉。DFA IV在酸性pH和高温下非常稳定，因此表明DFA IV可能适用于食品工业及相关领域。
