Ohta Kazuyoshi, Suetsugu Norio, Nakamura Toyohiko
Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, Miyazaki University, 1-1 Gakuen Kibanadai Nishi, Miyazaki 889-2192, Japan.
J Biosci Bioeng. 2002;94(1):78-80. doi: 10.1263/jbb.94.78.
A filamentous fungus, Rhizopus sp. strain TN-96, was isolated from rhizosphere soil samples. An extracellular inulinase was purified from the culture filtrate of strain TN-96 grown on inulin by DEAE-Cellulofine A-500 and Sephacryl S-200 HP chromatographies. The enzyme was homogeneous as judged by SDS-polyacrylamide gel electrophoresis, with an apparent M(r) of 83 kDa. The purified enzyme had specific activities of 17 U/mg toward inulin (I) and 0.32 U/mg toward sucrose (S) (I/S ratio, 53). Inulinase activity was optimal at pH 5.5 and 40 degrees C. The inulinase exhibited an apparent K(m) value of 9.0 mM for inulin. The enzyme also hydrolyzed raffinose, but not bacterial levan.
从根际土壤样品中分离出一株丝状真菌，根霉属菌株TN - 96。通过DEAE - Cellulofine A - 500和Sephacryl S - 200 HP色谱法从在菊粉上生长的菌株TN - 96的培养滤液中纯化出一种胞外菊粉酶。通过SDS - 聚丙烯酰胺凝胶电泳判断，该酶是纯一的，表观分子量为83 kDa。纯化后的酶对菊粉（I）的比活性为17 U/mg，对蔗糖（S）的比活性为0.32 U/mg（I/S比为53）。菊粉酶活性在pH 5.5和40℃时最佳。该菊粉酶对菊粉的表观K(m)值为9.0 mM。该酶还能水解棉子糖，但不能水解细菌果聚糖。
