Ito K, Ogasawara H, Sugimoto T, Ishikawa T
a National Research Institute of Brewing, 2-6-30, Takinogawa, Kita-ku , Tokyo 114 , Japan.
Biosci Biotechnol Biochem. 1992 Jan;56(4):547-50. doi: 10.1271/bbb.56.547.
Five extracellular endo-xylanases were recognized in the culture broth of shochu koji mold (Aspergillus kawachii, IFO 4308), and three major xylanases (XylA, XylB, and XylC) were purified and characterized. The molecular masses of XylA, XylB, and XylC were 35,000, 26,000, and 29,000, and isoelectric points were pH 6.7, 4.4, and 3.5, respectively. Amino acid compositions and other properties were studied and these three xylanases were found to be greatly different in their properties. These three xylanases, XylA, XylB, and XylC, were stable between pH 3-10, 3-10, and 1-9 and the optimum pHs were 5.5, 4.5, and 2.0, respectively. Consequently, these xylanases were acid stable xylanases, especially XylC was an acidophilic xylanase (acid xylanase). These xylanases produced various xylooligosaccharides including xylose from xylan and the main product was xylobiose in all xylanases. The production of acid xylanase (XylC) was enhanced with a low initial pH of the medium.
在烧酒曲霉菌（河合曲霉，IFO 4308）的培养液中鉴定出5种胞外内切木聚糖酶，并对3种主要木聚糖酶（XylA、XylB和XylC）进行了纯化和特性分析。XylA、XylB和XylC的分子量分别为35,000、26,000和29,000，等电点分别为pH 6.7、4.4和3.5。研究了它们的氨基酸组成和其他特性，发现这3种木聚糖酶在性质上有很大差异。这3种木聚糖酶XylA、XylB和XylC在pH 3 - 10、3 - 10和1 - 9之间稳定，最适pH分别为5.5、4.5和2.0。因此，这些木聚糖酶是耐酸木聚糖酶，尤其是XylC是一种嗜酸木聚糖酶（酸性木聚糖酶）。这些木聚糖酶能从木聚糖产生包括木糖在内的各种木寡糖，所有木聚糖酶的主要产物都是木二糖。酸性木聚糖酶（XylC）的产生在培养基初始pH较低时会增强。
