Tarentino A L, Maley F
J Biol Chem. 1976 Nov 10;251(21):6537-43.
An endo-beta-N-acetylglucosaminidase has been purified extensively from hen oviduct extracts and found to have a somewhat broader substrate specificity than the previously reported endoglycosidases from Dipolcoccus pneumoniae and Streptomyces plicatus (Arakawa, M., and Muramatsu, T. (1974) J. Biochem. (Tokyo) 76, 307-317; Tarentino, A. L., and Maley, F. (1975) Biochem. Biophys. Res. Commun. 67, 455-462. The enzyme was shown to hydrolyze and di-N-acetylchitobiosyl bond in such compounds as Asn(GlcNAc)2(Man)3, Asn(GlcNAc)2(Man)5, Asn(GlcNAc)2(Man)6 and a glycopeptide from immunoglobulin M, (aa)x-Asn(GlcNAc)2(Man)3(Fuc)1. The capacity to hydrolyze the latter compound is a characteristic of the endoglycosidase from D. pneumoniae, but not that from S. plicatus. Competitive inhibition studies indicate that a single enzyme in the hen oviduct endoglycosidase preparation is probably responsible for hydrolyzing both fucose-containing the fucose-depleted substrates. The existence of an endo-beta-N-acetylglucosaminidase in animal tissue may explain why oligosaccharides with N-acetylglucosamine on the reducing terminus accumulate in certain lysosomal storage diseases.
一种内切-β-N-乙酰氨基葡萄糖苷酶已从母鸡输卵管提取物中得到广泛纯化，发现其底物特异性比先前报道的来自肺炎双球菌和褶皱链霉菌的内切糖苷酶稍广（荒川，M.，和村松，T.（1974年）《生物化学杂志》（东京）76，307 - 317；塔伦蒂诺，A.L.，和马利，F.（1975年）《生物化学与生物物理研究通讯》67，455 - 462）。该酶被证明能水解诸如Asn(GlcNAc)2(Man)3、Asn(GlcNAc)2(Man)5、Asn(GlcNAc)2(Man)6以及免疫球蛋白M的糖肽(aa)x - Asn(GlcNAc)2(Man)3(Fuc)1等化合物中的二-N-乙酰壳二糖键。水解后一种化合物的能力是肺炎双球菌内切糖苷酶的特征，而非褶皱链霉菌内切糖苷酶的特征。竞争性抑制研究表明，母鸡输卵管内切糖苷酶制剂中的单一酶可能负责水解含岩藻糖和不含岩藻糖的底物。动物组织中存在内切-β-N-乙酰氨基葡萄糖苷酶可能解释了为什么在某些溶酶体贮积病中还原端带有N-乙酰氨基葡萄糖的寡糖会积累。
