泡盛曲霉IFO 4033中两种α-L-阿拉伯呋喃糖苷酶的纯化及底物特异性
Purification and substrate specificities of two alpha-L-arabinofuranosidases from Aspergillus awamori IFO 4033.
作者信息
Kaneko S, Arimoto M, Ohba M, Kobayashi H, Ishii T, Kusakabe I
机构信息
Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennoodai, Tsukuba, Ibaraki 305, Japan.
出版信息
Appl Environ Microbiol. 1998 Oct;64(10):4021-7. doi: 10.1128/AEM.64.10.4021-4027.1998.
alpha-L-Arabinofuranosidases I and II were purified from the culture filtrate of Aspergillus awamori IFO 4033 and had molecular weights of 81,000 and 62,000 and pIs of 3.3 and 3.6, respectively. Both enzymes had an optimum pH of 4.0 and an optimum temperature of 60 degreesC and exhibited stability at pH values from 3 to 7 and at temperatures up to 60 degrees C. The enzymes released arabinose from p-nitrophenyl-alpha-L-arabinofuranoside, O-alpha-L-arabinofuranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-x ylopyranose, and arabinose-containing polysaccharides but not from O-beta-D-xylopyranosyl-(1-->2)-O-alpha-L-arabinofuranosyl-(1-->3)-O-b eta-D-xylopyranosyl-(1-->4)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyra nose. alpha-L-Arabinofuranosidase I also released arabinose from O-beta-D-xylopy-ranosyl-(1-->4)-[O-alpha-L-arabinofuranosyl- (1-->3)]- O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose. However, alpha-L-arabinofuranosidase II did not readily catalyze this hydrolysis reaction. alpha-L-Arabinofuranosidase I hydrolyzed all linkages that can occur between two alpha-L-arabinofuranosyl residues in the following order: (1-->5) linkage > (1-->3) linkage > (1-->2) linkage. alpha-L-Arabinofuranosidase II hydrolyzed the linkages in the following order: (1-->5) linkage > (1-->2) linkage > (1-->3) linkage. alpha-L-Arabinofuranosidase I preferentially hydrolyzed the (1-->5) linkage of branched arabinotrisaccharide. On the other hand, alpha-L-arabinofuranosidase II preferentially hydrolyzed the (1-->3) linkage in the same substrate. alpha-L-Arabinofuranosidase I released arabinose from the nonreducing terminus of arabinan, whereas alpha-L-arabinofuranosidase II preferentially hydrolyzed the arabinosyl side chain linkage of arabinan.
α-L-阿拉伯呋喃糖苷酶I和II从泡盛曲霉IFO 4033的培养滤液中纯化得到，分子量分别为81,000和62,000，pI分别为3.3和3.6。两种酶的最适pH均为4.0，最适温度为60℃，在pH值3至7以及温度高达60℃时表现出稳定性。这些酶能从对硝基苯基-α-L-阿拉伯呋喃糖苷、O-α-L-阿拉伯呋喃糖基-(1→3)-O-β-D-木吡喃糖基-(1→4)-D-木吡喃糖以及含阿拉伯糖的多糖中释放出阿拉伯糖，但不能从O-β-D-木吡喃糖基-(1→2)-O-α-L-阿拉伯呋喃糖基-(1→3)-O-β-D-木吡喃糖基-(1→4)-O-β-D-木吡喃糖基-(1→4)-D-木吡喃糖中释放阿拉伯糖。α-L-阿拉伯呋喃糖苷酶I还能从O-β-D-木吡喃糖基-(1→4)-[O-α-L-阿拉伯呋喃糖基-(1→3)]-O-β-D-木吡喃糖基-(1→4)-D-木吡喃糖中释放阿拉伯糖。然而，α-L-阿拉伯呋喃糖苷酶II不易催化这种水解反应。α-L-阿拉伯呋喃糖苷酶I按以下顺序水解两个α-L-阿拉伯呋喃糖基残基之间可能出现的所有连接：(1→5)连接＞(1→3)连接＞(1→2)连接。α-L-阿拉伯呋喃糖苷酶II按以下顺序水解连接：(1→5)连接＞(1→2)连接＞(1→3)连接。α-L-阿拉伯呋喃糖苷酶I优先水解支链阿拉伯三糖的(1→5)连接。另一方面，α-L-阿拉伯呋喃糖苷酶II优先水解同一底物中的(1→3)连接。α-L-阿拉伯呋喃糖苷酶I从阿拉伯聚糖的非还原末端释放阿拉伯糖，而α-L-阿拉伯呋喃糖苷酶II优先水解阿拉伯聚糖的阿拉伯糖基侧链连接。
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