Department of Life and Nutritional Science, Fukuyama University, 1-985 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292, Japan,
Appl Biochem Biotechnol. 2014 Mar;172(5):2650-60. doi: 10.1007/s12010-013-0691-3. Epub 2014 Jan 14.
Streptomyces sp I10-1 α-L-arabinofuranosidase efficiently produced L-arabinose from high arabinose-content corn hull arabinoxylan (ratio of arabinose to xylose, 0.6). The optimum pH at 40 °C was around 6, and the enzyme was stable from pH 5 to 11. The optimum temperature was 50 °C at pH 5, and the activity was stable at 40 °C. The enzymatic activity against corn hull arabinoxylan was 2.3 times higher than towards p-nitrophenyl-α-L-arabinofuranoside. Approximately 45% L-arabinose recovery was achieved from corn hull arabinoxylan. It was considered that L-arabinose residues not removed by the enzyme were attributable to those linked with ferulic acid. The open reading frame of the enzyme gene consisted of 1,224 bp, and the predicted peptide was 408 amino acids, which corresponded to a molecular size of 45, 248 Da. It was presumed that the smaller molecular size (31,000 Da) estimated on SDS-PAGE resulted from proteolysis by proteases. I10-1 α-L-arabinofuranosidase belongs to the Alpha-L-AF C superfamily, which is associated with glycoside hydrolase family 51, but the properties were unique.
链霉菌 I10-1α-L-阿拉伯呋喃糖苷酶能够有效地从高阿拉伯糖含量的玉米皮阿拉伯木聚糖（阿拉伯糖与木糖的比例为 0.6）中生产 L-阿拉伯糖。在 40°C 时，最适 pH 值约为 6，该酶在 pH5 到 11 之间稳定。在 pH5 时，最适温度为 50°C，在 40°C 时活性稳定。该酶对玉米皮阿拉伯木聚糖的酶活性比对 p-硝基苯-α-L-阿拉伯呋喃糖苷高 2.3 倍。从玉米皮阿拉伯木聚糖中可获得约 45%的 L-阿拉伯糖回收率。据认为，酶未去除的 L-阿拉伯糖残基归因于与阿魏酸相连的那些残基。酶基因的开放阅读框由 1224bp 组成，预测的肽为 408 个氨基酸，对应于 45248Da 的分子大小。据推测，SDS-PAGE 上估计的较小分子大小（31000Da）是由蛋白酶的蛋白水解作用引起的。I10-1α-L-阿拉伯呋喃糖苷酶属于 Alpha-L-AF C 超家族，与糖苷水解酶家族 51 相关，但性质独特。
