Nakada T, Maruta K, Tsusaki K, Kubota M, Chaen H, Sugimoto T, Kurimoto M, Tsujisaka Y
Hayashibara Biochemical Laboratories, Inc., Okayama, Japan.
Biosci Biotechnol Biochem. 1995 Dec;59(12):2210-4. doi: 10.1271/bbb.59.2210.
Arthrobacter sp. Q36 produces a novel enzyme, maltooligosyl trehalose synthase, which catalyzes the conversion of maltooligosaccharide into the non-reducing saccharide, maltooligosyl trehalose (alpha-maltooligosyl alpha-D-glucoside) by intramolecular transglycosylation. The enzyme was purified from a cell-free extract to an electrophoretically homogeneous state by successive column chromatography on Sepabeads FP-DA13, DEAE-Sephadex A-50, Ultrogel AcA44, and Butyl-Toyopearl 650M. The enzyme was specific for maltooligosaccharides except maltose, and catalyzed the conversion to form maltooligosyl trehalose. The Km of the enzyme for maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were 22.9 mM, 8.7 mM, 1.4 mM, and 0.9 mM, respectively. The enzyme had a molecular mass of 81,000 by SDS-polyacrylamide gel electrophoresis and a pI of 4.1 by gel isoelectrofocusing. The N-terminal and C-terminal amino acids of the enzyme were methionine and serine, respectively. The enzyme showed the highest activity at pH 7.0 and 40 degrees C, and was stable from pH 6.0 to 9.5 and up to 40 degrees C. The enzyme activity was inhibited by Hg2+ and Cu2+.
节杆菌属Q36菌株产生一种新型酶——麦芽寡糖海藻糖合酶，该酶通过分子内转糖基作用催化麦芽寡糖转化为非还原性糖类麦芽寡糖基海藻糖（α-麦芽寡糖基α-D-葡萄糖苷）。通过在Sepabeads FP-DA13、DEAE-葡聚糖A-50、Ultrogel AcA44和丁基-琼脂糖650M上连续进行柱色谱，从无细胞提取物中纯化该酶至电泳纯状态。该酶对除麦芽糖外的麦芽寡糖具有特异性，并催化形成麦芽寡糖基海藻糖。该酶对麦芽四糖、麦芽五糖、麦芽六糖和麦芽七糖的Km值分别为22.9 mM、8.7 mM、1.4 mM和0.9 mM。通过SDS-聚丙烯酰胺凝胶电泳测得该酶的分子量为81,000，通过凝胶等电聚焦测得其pI为4.1。该酶的N端和C端氨基酸分别为甲硫氨酸和丝氨酸。该酶在pH 7.0和40℃时表现出最高活性，在pH 6.0至9.5以及高达40℃的条件下稳定。该酶的活性受到Hg2+和Cu2+的抑制。
