Characterization of a novel enzyme involved in the degradation of plant proteoglycans

从阿维链霉菌中分离到一种能将阿拉伯糖从增稠剂阿拉伯半乳聚糖中分离出来的新型酶- β - l -arabinopyranosidase，并对其三维结构进行了解析。该酶与α - d -半乳糖苷酶一样属于糖苷水解酶家族。α - d -半乳糖苷酶催化袋中的一个天冬氨酸在β - l -阿拉伯葡萄糖苷酶催化袋中转化为谷氨酸，其残基调节酶的活性。此外，它还具有阿拉伯吡喃糖结合模块。

A novel enzyme, beta-L-arabinopyranosidase, that liberates arabinose from thickening agent arabinogalactan was isolated from Streptomyces avermitilis, and the three dimentional structure was resolved. The enzyme belongs to the glycoside hydrolase family as same as alpha-D-galactosidases. One aspartic acid in the catalytic pocket of alpha-D-galactosidase changed to glutamic acid in that of beta-L-arabinopyranosidase, and the residue modulates the enzyme activity. Addifionally, it has an arabinopyranose-binding module.