Takahashi N, Horikawa T, Mizuno F, Takamori K
Bull Tokyo Med Dent Univ. 1980 Jun;27(2):79-88.
Crude enzymes (En(C)) which hydrolyze insoluble glucan produced by Streptococcus mutans FA-1 were extracted from Bacteroides oralis obtained from human dental plaque. Extracellular insoluble glucan of S. mutans (IsG) and the one which was partially modified by Smith degradation (M-IsG) were used as substrates. Commercial dextran (M.W. 2,000,000) was used as control. Composition of the types of glucosidic linkages of the glucans was determined by methylation analysis. The ratio of the alpha-(1--6) linkage and alpha-(1--3) linkage was 96.3% and 0.5% for dextran, 29.2% and 55.1% for IsG and 11.9% and 84.9% for M-IsG. En(C) was extracted by salting out of the culture of B. oralis with 60% saturation of ammonium sulfate. En(C) hydrolyzed IsG, M-IsG and dextran, whereas commercial dextranase (alpha-1,6 glucanase) hydrolyzed only dextran. IsG was treated with the commercial dextranase until no glucose was detected in the medium, and the remaining material was used for the substrate of enzymes. Release of glucose was detected from the substrate by treatment with En(C), but not with commercial dextranase. These results indicated that En(C) of Bacteroides oralis contained at least two types of glucanase, one being dextranase which hydrolyzes the alpha-(1--6) linkage and the other the so-called mutanase which hydrolyzes the alpha-(1--3) linkage.
从人牙菌斑中分离得到的口腔拟杆菌中提取出能水解变形链球菌FA-1产生的不溶性葡聚糖的粗酶（En(C)）。以变形链球菌的细胞外不溶性葡聚糖（IsG）和经史密斯降解部分修饰的葡聚糖（M-IsG）作为底物。以商业葡聚糖（分子量2,000,000）作为对照。通过甲基化分析确定葡聚糖中糖苷键类型的组成。对于葡聚糖，α-(1→6)键和α-(1→3)键的比例分别为96.3%和0.5%；对于IsG，分别为29.2%和55.1%；对于M-IsG，分别为11.9%和84.9%。通过用60%饱和度的硫酸铵对口腔拟杆菌培养物进行盐析来提取En(C)。En(C)能水解IsG、M-IsG和葡聚糖，而商业葡聚糖酶（α-1,6葡聚糖酶）仅能水解葡聚糖。用商业葡聚糖酶处理IsG直至培养基中检测不到葡萄糖，剩余物质用作酶的底物。用En(C)处理底物可检测到葡萄糖的释放，而用商业葡聚糖酶处理则检测不到。这些结果表明，口腔拟杆菌的En(C)至少包含两种类型的葡聚糖酶，一种是水解α-(1→6)键的葡聚糖酶，另一种是所谓的变聚糖酶，它能水解α-(1→3)键。
