Role of the carbohydrate moiety of a glucoamylase from Aspergillus awamori var. kawachi in the digestion of raw starch.
Role of the carbohydrate moiety of a glucoamylase from Aspergillus awamori var. kawachi in the digestion of raw starch.
复制标题
泡盛曲霉葡糖淀粉酶碳水化合物部分的作用
DOI：
10.1271/bbb.59.16
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
S. Hayashida
中科院分区：
文献类型：
--
作者：
M. Goto;E. Kuwano;W. Kanlayakrit;S. Hayashida
研究了泡盛曲霉突变株产生的糖化酶（GA MU-H）对生淀粉的消化作用。kawachi与O-连接到Gp-I区域（A470-V514）的甘露糖苷链密切相关，但与N-连接到GA MU-H的催化GAI'结构域的糖链不相关。葡萄糖残基部分取代甘露糖残基导致生淀粉消化显著降低。通过用D2 O取代反应混合物中的H2O，GA MU-H的生淀粉消化降低到30 ℃时的80%，尽管GA MU-H的可溶性淀粉的水解速率和结合β-环糊精的能力没有改变。甘油，作为一种抗离液剂，降低GA MU-H的生淀粉消化显着。但以可溶性淀粉为底物时，对酶活性无影响。用生淀粉消化葡萄糖淀粉酶有效地消化生淀粉需要与Gp-I区域O-连接的甘露糖苷链，这被认为是通过与水的相互作用来促进生淀粉的消化。
The digestion of raw starch by a glucoamylase (GA MU-H) from a mutant strain of Aspergillus awamori var. kawachi was closely correlated with mannoside chains O-linked to the Gp-I region (A470-V514), but not sugar chains N-linked to catalytic GAI' domain of GA MU-H. The partial replacement of mannose residues by glucose residues led to a significant decrease raw starch digestion. By the substitution of D2O for H2O in the reaction mixture, the raw starch digestion of GA MU-H decreased to 80% of that at 30 degrees C, although the rate of hydrolysis of soluble starch by and the ability to bind beta-cyclodextrin of GA MU-H were unchanged. Glycerol, known as an antichaotropic reagent, decreased the raw starch digestion of GA MU-H significantly. However, it did not have any effect on the enzymatic activity for soluble starch when soluble starch was the substrate. The efficient digestion of raw starch with raw starch-digesting glucoamylase needed the mannoside chains O-linked to the Gp-I region, which were suggested to contribute to digestion of raw starch through the interaction with water.