Microbiology Group, UNIDO ICGEB, Padriciano 99, I-34012, Trieste, Italy, and Department of Agricultural Chemical Technology, Technical University of Budapest, Gellért tér 4, H-1111 Budapest, Hungary.
Appl Environ Microbiol. 1992 Nov;58(11):3466-71. doi: 10.1128/aem.58.11.3466-3471.1992.
Xylan-degrading enzymes were induced when Phanerochaete chrysosporium was grown at 30 degrees C in shake flask media containing xylan, Avicel PH 102, or ground corn stalks. The highest xylanase activity was produced in the corn stalk medium, while the xylan-based fermentation resulted in the lowest induction. Analytical and preparative isoelectric focusing were used to characterize xylanase multienzyme components. Preparative focusing was performed only with the cultures grown on Avicel and corn stalk. Of over 30 protein bands separated by analytical focusing from the Avicel and corn stalk media, three main groups (I, II, and III) of about five isoenzymes each showed xylanase activity when a zymogram technique with a xylan overlay was used. Enzyme assays revealed the presence of 1,4-beta-endoxylanase and arabinofuranosidase activities in all three isoenzyme groups separated by preparative isoelectric focusing. beta-Xylosidase activity appeared in the first peak and also as an independent peak between peaks II and III. Denatured molecular masses for the three isoenzyme groups were found to be between 18 and 90 kDa, and pI values were in the range of 4.2 to 6.0. beta-Xylosidase has an apparent molecular mass of 20, 30, and 90 kDa (peak I) and 18 and 45 kDa (independent peak), indicating a trimer and dimer structure, respectively, with pI values of 4.2 and 5.78, respectively. Three more minor xylanase groups were produced on corn stalk medium: a double peak in the acidic range (pI 6.25 to 6.65 and 6.65 to 7.12) and two minor peaks in the alkaline range (pI 8.09 to 8.29 and 9.28 to 9.48, respectively). The profile of xylanases separated by isoelectric focusing (zymogram) of culture filtrate from cells grown on corn stalk media was more complex than that of culture supernatants from cells grown on cellulose. The pH optima of the three major xylanase groups are in the range of pH 4 to 5.5.
当黄孢原毛平革菌在 30°C 下的摇瓶培养基中生长时，会诱导产生木聚糖降解酶，该培养基中含有木聚糖、Avicel PH 102 或粉碎的玉米秸秆。在玉米秸秆培养基中产生了最高的木聚糖酶活性，而基于木聚糖的发酵导致最低的诱导。分析和制备等电聚焦用于表征木聚糖酶多酶成分。仅对在 Avicel 和玉米秸秆上生长的培养物进行了制备聚焦。在分析聚焦中，从 Avicel 和玉米秸秆培养基中分离出的 30 多个蛋白质带中，当使用木聚糖覆盖的同工酶技术进行分析时，三个主要组（I、II 和 III）中的约五个同工酶各自显示出木聚糖酶活性。酶测定显示，在通过制备等电聚焦分离的所有三个同工酶组中都存在 1,4-β-内切木聚糖酶和阿拉伯呋喃糖苷酶活性。β-木糖苷酶活性出现在第一个峰中，也出现在峰 II 和 III 之间的独立峰中。发现三个同工酶组的变性分子量在 18 到 90 kDa 之间，等电点在 4.2 到 6.0 范围内。β-木糖苷酶的表观分子量分别为 20、30 和 90 kDa（峰 I）和 18 和 45 kDa（独立峰），分别表明其具有三聚体和二聚体结构，等电点分别为 4.2 和 5.78。在玉米秸秆培养基上还产生了三个较小的木聚糖酶组：在酸性范围内的双峰（等电点 6.25 至 6.65 和 6.65 至 7.12）和碱性范围内的两个较小峰（等电点分别为 8.09 至 8.29 和 9.28 至 9.48）。在玉米秸秆培养基上生长的细胞的培养滤液通过等电聚焦（同工酶）分离的木聚糖酶图谱比在纤维素上生长的细胞的培养上清液更为复杂。三个主要木聚糖酶组的最适 pH 值在 pH 4 到 5.5 范围内。
