Sreenath H K, Joseph R
Folia Microbiol (Praha). 1982;27(2):107-15. doi: 10.1007/BF02879768.
Fractionation of extracellular xylan hydrolases of a strain of Streptomyces exfoliatus MC1 (by salting out, molecular sieving and ion exchange chromatography) revealed the presence of five species of the enzyme. Three major fractions could be purified to homogeneity; two were apparently endohydrolases and the third an exo-xylan hydrolase. The three fractions showed different degrees of affinity to the substrate and differed considerably in their substrate specificities. One of the endo-enzymes was specific to xylan while the other could also attack cellulose, inulin and pectin. The exo-enzyme showed xylanolytic and cellulolytic functions only. The three fractions further differed in their response to the presence of metal ions, mercapto reagents and compounds. Although the pH and temperature optima were different, the three fractions functioned synergistically in the hydrolysis of xylan.
对一株脱落链霉菌MC1的细胞外木聚糖水解酶进行分级分离（通过盐析、分子筛和离子交换色谱法），发现存在五种该酶。三种主要级分可纯化至均一；两种显然是内切水解酶，第三种是外切木聚糖水解酶。这三种级分对底物表现出不同程度的亲和力，并且它们的底物特异性差异很大。其中一种内切酶对木聚糖具有特异性，而另一种还可以作用于纤维素、菊粉和果胶。外切酶仅表现出木聚糖分解和纤维素分解功能。这三种级分对金属离子、巯基试剂和化合物的存在的反应也有所不同。尽管最适pH和温度不同，但这三种级分在木聚糖水解中发挥协同作用。
