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

从阿维链霉菌中分离得到一种能从增稠剂阿拉伯半乳糖中释放阿拉伯糖的新型酶--β-L-阿拉伯吡喃糖苷酶，并对其三维结构进行了解析。该酶与α-D-半乳糖苷酶同属糖苷水解酶家族。α-D-半乳糖苷酶催化口袋中的一个天冬氨酸在β-L-阿拉伯吡喃糖苷酶催化口袋中转变为谷氨酸，残基对酶活性起调控作用。此外，它还有一个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.