α-glucosidase mutant catalyzes "α-glycosynthase"-type reaction
α-glucosidase mutant catalyzes "α-glycosynthase"-type reaction
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DOI：
10.1271/bbb.66.928
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发表时间：
2002-04-01
影响因子：
1.6
通讯作者：
Chiba, S
中科院分区：
文献类型：
--
作者：
Okuyama, M;Mori, H;Chiba, S
在裂殖酵母α-葡萄糖苷酶中用甘氨酸取代催化亲核试剂Asp481，消除了该酶的水解性。该突变酶(D481G)催化β-氟代葡萄糖苷和4-硝基苯基(PNP)α-葡萄糖苷形成α-葡萄糖苷键，生成两种PNPα-二葡萄糖苷：α-异麦芽糖苷和α-麦芽糖苷。两种产物均未被D481G水解，PNPα-异麦芽糖苷和α-麦芽糖苷的产率分别为41%和29%。PNP单糖苷，如α-木糖苷、α-甘露糖苷或β-葡萄糖苷作为底物，而PNPα-半乳糖苷和麦芽糖不能作为底物。在α-葡萄糖基氟化物和PNPα-葡萄糖苷的组合中未观察到检测到的产物。这项研究是关于形成α-糖苷键的“α-糖合成酶”类型反应的第一个报告。
Replacement of the catalytic nucleophile Asp481 by glycine in Schizosaccharomyces pombe alpha-glucosidase eliminated the hydrolytic activity. The mutant enzyme (D481G) was found to catalyze the formation of an alpha-glucosidic linkage from beta-glucosyl fluoride and 4-nitrophenyl (PNP) alpha-glucoside to produce two kinds of PNP alpha-diglucosides, alpha-isomaltoside and alpha-maltoside. The two products were not hydrolyzed by D481G, giving 41 and 29% yields of PNP alpha-isomaltoside and alpha-maltoside, respectively. PNP monoglycosides, such as alpha-xyloside, alpha-mannoside, or beta-glucoside, acted as the substrate, but PNP alpha-galactoside and maltose could not. No detectable product was observed in the combination of alpha-glucosyl fluoride and PNP alpha-glucoside. This study is the first report on an "alpha-glycosynthase"-type reaction to form an alpha-glycosidic linkage.