两种黑曲霉产生的α-L-阿拉伯呋喃糖苷酶的底物特异性
Substrate specificities of alpha-L-arabinofuranosidases produced by two species of Aspergillus niger.
作者信息
Kaneko S, Ishii T, Kobayashi H, Kusakabe I
机构信息
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
出版信息
Biosci Biotechnol Biochem. 1998 Apr;62(4):695-9. doi: 10.1271/bbb.62.695.
Precise substrate specificities of alpha-L-arabinofuranosidases from Aspergillus niger 5-16 and Aspergillus niger (Megazyme) were investigated. Both enzymes hydrolyzed arabinan and debranched-arabinan at almost the same rate. The alpha-L-Arabinofuranosidase from A. niger (Megazyme) preferentially released arabinosyl side-chains of arabinan. The enzyme tore off both arabinoses attached to O-alpha-L-arabinofuranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1--> 4)-D-xylopyranose and O-beta-D-xylopyranosyl-(1-->4)-[O-alpha-L- arabinofuranosyl-(1-->3)]-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose, but did not tear off xylosyl-arabinose from O-beta-D-xylopyranosyl-(1-->2)-O-alpha-L-arabinofuranosyl-(1-->3) -O-beta-D-xylopyranosyl-(1-->4)-O-beta-D-xylopyranosyl-(1-->4)-D- xylopyranose. The enzyme from A. niger (Megazyme) hydrolyzed methyl 2-O-, methyl 3-O- and methyl 5-O-alpha-L-arabinofuranosyl-alpha-L-arabinofuranosides to arabinose and methyl alpha-L-arabinofuranoside in the order of (1-->5)->(1-->2)->(1-->3)-linkages. On the other hand, alpha-L-arabinofuranosidase from A. niger 5-16 successively liberated the arabinose of arabinan from non-reducing terminals. The enzyme hydrolyzed in the order of (1-->2- > (1-->3)- > (1-->5)-linkages. Both of the enzymes hydrolyzed the (1-->3)-linkage more than the (1-->5)-linkage of methyl 3,5-di-O-alpha-L-arabinofuranosyl-alpha-L-arabinofuranoside.
对黑曲霉5-16和黑曲霉（Megazyme）来源的α-L-阿拉伯呋喃糖苷酶的精确底物特异性进行了研究。两种酶以几乎相同的速率水解阿拉伯聚糖和去支链阿拉伯聚糖。黑曲霉（Megazyme）来源的α-L-阿拉伯呋喃糖苷酶优先释放阿拉伯聚糖的阿拉伯糖基侧链。该酶能切断连接在O-α-L-阿拉伯呋喃糖基-(1→3)-O-β-D-木吡喃糖基-(1→4)-D-木吡喃糖和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-木吡喃糖上的两个阿拉伯糖，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-木吡喃糖上切断木糖基-阿拉伯糖。黑曲霉（Megazyme）来源的酶将2-O-甲基-α-L-阿拉伯呋喃糖基-α-L-阿拉伯呋喃糖苷、3-O-甲基-α-L-阿拉伯呋喃糖基-α-L-阿拉伯呋喃糖苷和5-O-甲基-α-L-阿拉伯呋喃糖基-α-L-阿拉伯呋喃糖苷水解为阿拉伯糖和α-L-阿拉伯呋喃糖甲基苷，其顺序为(1→5)＞(1→2)＞(1→3)连接。另一方面，黑曲霉5-16来源的α-L-阿拉伯呋喃糖苷酶从非还原末端依次释放阿拉伯聚糖的阿拉伯糖。该酶的水解顺序为(1→2)＞(1→3)＞(1→5)连接。两种酶对3,5-二-O-α-L-阿拉伯呋喃糖基-α-L-阿拉伯呋喃糖苷的(1→3)连接的水解程度均大于(1→5)连接。
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