Transgalactosylation Catalyzed by<i>α</i>-Galactosidase from<i>Candida guilliermondii</i>H-404
作者:Hiroyuki Hashimoto、Chie Katayama、Masaru Goto、Tatsuyuki Okinaga、Sumio Kitahata
DOI:10.1271/bbb.59.619
日期:1995.1
The thermostable α-galactosidase from Candida guilliermondii H-404 synthesized self-transfer products in the absence of a suitable acceptor. The main self-transfer product, using melibiose as a donor substrate, was O-α-D-galactosyl-(1,6)-O-α-D-galactosyl-(1,6)-D-glucose. This enzyme had a wide acceptor specificity. D-Glucose, D-galactose, maltose, maltitol, and 1,4-butandiol were the most effective acceptors in the transgalactosylation catalyzed by this enzyme. The enzyme could also transfer α-galactosyl residues to pentoses (L-arabinose, D-xylose, and D-ribose) and methyl pentoses (D-fucose and L-rhamnose). The main transfer products to lactose, maltose, and sucrose as acceptors were identified as O-α-D-galactosyl-(1,6)-O-β-D-galactosyl-(1,4)-D-glucose, O-α-D-galactosyl-(1,6)-O-α-D-glucosyl-(1,4)-D-glucose, and O-α-D-galactosyl-(1,6)-O-α-D-glucosyl-(1,2)-β-D-fructoside (raffinose), respectively.
来自Candida guilliermondii H-404的热稳定α-半乳糖苷酶在缺乏合适受体的情况下合成了自转移产物。主要自转移产物是以蜜二糖为供体底物的情况下,形成的O-α-D-半乳糖基-(1,6)-O-α-D-半乳糖基-(1,6)-D-葡萄糖。该酶具有广泛的受体特异性。在由该酶催化的转半乳糖作用中,D-葡萄糖、D-半乳糖、麦芽糖、麦芽糖醇和1,4-丁二醇是最有效的受体。该酶还能将α-半乳糖基转移至戊糖(L-阿拉伯糖、D-木糖和D-核糖)和甲基戊糖(D-岩藻糖和L-鼠李糖)。以乳糖、麦芽糖和蔗糖为受体时,主要转移产物分别被鉴定为O-α-D-半乳糖基-(1,6)-O-β-D-半乳糖基-(1,4)-D-葡萄糖、O-α-D-半乳糖基-(1,6)-O-α-D-葡萄糖基-(1,4)-D-葡萄糖和O-α-D-半乳糖基-(1,6)-O-α-D-葡萄糖基-(1,2)-β-D-果糖苷(棉子糖)。