Tenkanen M, Luonteri E, Teleman A
VTT Biotechnology and Food Research, Finland.
FEBS Lett. 1996 Dec 16;399(3):303-6. doi: 10.1016/s0014-5793(96)01313-0.
The action of beta-xylosidase from Trichoderma reesei against different substituted xylo-oligosaccharides was studied. The enzyme cleaved off all unsubstituted xylose units from the non-reducing end of 1,2-linked uronic acid substituted xylo-oligosaccharides. Surprisingly, an L-arabinofuranosyl group linked alpha-1,3 to the xylopyranosyl ring was found to protect the beta-1,4-xylosidic linkage before the substituted xylose unit from being cleaved by the beta-xylosidase. Most probably the 1,3-linked substituent sterically hinders the hydrolysis. According to the results of the present work, beta-xylosidase of T. reesei is not able to remove all unsubstituted xylose units from the non-reducing end of substituted xylo-oligosaccharides, as had been believed previously.
研究了里氏木霉β-木糖苷酶对不同取代的木寡糖的作用。该酶从1,2-连接的糖醛酸取代的木寡糖的非还原端切下所有未取代的木糖单元。令人惊讶的是，发现与吡喃木糖环α-1,3连接的L-阿拉伯呋喃糖基可保护取代木糖单元之前的β-1,4-木糖苷键不被β-木糖苷酶切割。很可能1,3-连接的取代基在空间上阻碍了水解。根据本研究结果，里氏木霉的β-木糖苷酶不能像以前认为的那样从取代木寡糖的非还原端去除所有未取代的木糖单元。
