Haneda K, Inazu T, Yamamoto K, Kumagai H, Nakahara Y, Kobata A
Hoguchi Institute, Tokyo, Japan.
Carbohydr Res. 1996 Oct 4;292:61-70. doi: 10.1016/s0008-6215(96)91025-3.
The endo-beta-N-acetylglucosaminidase (endo-beta-GlcNAc-ase) of Mucor hiemalis, endo-M, was found to transfer the sialo complex-type oligosaccharides from transferrin glycopeptide to the N-acetylglucosamine (GlcNAc) moieties of peptidyl-GlcNAc. Disialo complex-type oligosaccharide of transferrin glycopeptide was transferred to 9-fluorenylmethyloxycarbonyl (Fmoc)-asparaginyl-N-acetylglucosaminide (Fmoc-Asn-GlcNAc) by endo-M in a high yield. The structure of the reaction product was confirmed to be Fmoc-Asn-(GlcNAc)2-Man-(Man-GlcNac-Gal-NeuAc)2 by mass spectrometry. Endo-M also transferred disialo complex-type oligosaccharide to the GlcNAc residue of chemically synthesized H-Ile-Asn(GlcNAc)-Ala-Thr-Leu-OH. Asn-linked asialo complex-type oligosaccharide and Asn-linked high-mannose type oligosaccharide were also effective as oligosaccharide donors. Transfer of disialo complex-type oligosaccharide to the GlcNAc-peptide was the most effective among the three types of oligosaccharides, although the disialo complex-type oligosaccharide attached to the peptide was the poorest substrate for the hydrolytic activity of endo-M.
发现毛霉的内切β-N-乙酰氨基葡萄糖苷酶（内切β-GlcNAc酶），即内切M，可将转铁蛋白糖肽中的唾液酸复合类型寡糖转移至肽基-N-乙酰氨基葡萄糖（GlcNAc）的N-乙酰氨基葡萄糖部分。转铁蛋白糖肽的二唾液酸复合类型寡糖被内切M以高产率转移至9-芴甲氧羰基（Fmoc）-天冬酰胺基-N-乙酰氨基葡萄糖苷（Fmoc-Asn-GlcNAc）。通过质谱法确认反应产物的结构为Fmoc-Asn-(GlcNAc)2-Man-(Man-GlcNac-Gal-NeuAc)2。内切M还将二唾液酸复合类型寡糖转移至化学合成的H-Ile-Asn(GlcNAc)-Ala-Thr-Leu-OH的GlcNAc残基上。Asn连接的去唾液酸复合类型寡糖和Asn连接的高甘露糖型寡糖作为寡糖供体也有效。在这三种类型的寡糖中，二唾液酸复合类型寡糖向GlcNAc-肽的转移最为有效，尽管连接到肽上的二唾液酸复合类型寡糖是内切M水解活性最差的底物。
