Studies on the Biosynthetic Mechanism of Bioactive Sulfated Glycosaminoglycans

生物活性硫酸化糖胺聚糖的生物合成机制研究

• 批准号: 08044327
• 负责人: SUGAHARA Kazuyuki
• 金额: $ 1.92万
• 依托单位: Kobe Pharmaceutical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08044327/
• 关键词: Proteoglycan; Glycosaminoglycan; Sulfation; Chondroitin Sulfate; Heparin; Heparan Sulfate; 糖転移酵素

(1)Using mouse mastcytoma microsomal fraction as an enzyme source, UDP-GalNAc as a sugar donor and a synthetic glycoserine GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser as an sugar acceptor, a GalNAc transfer was observed. However, the linkage was found to be alpha-but not beta-linked. This was in accordance with our previous observation obtained using the enzyme preparation purified from fetal bovine serum.(2)The above activity was not observed with GlcAbeta1-3Gal(4-O-sulfate)beta1-3Galbeta1-4Xylbeta1-O-Ser as an sugar acceptor, indicating that the sulfate group inhibited the alpha-GalNAc transferase reaction.(3)On the other hand, no alpha-GlcNAc transferase activity expected for heparin biosynthesis was observed when assayd under similar incubation conditions except that UDP-GlcNAc was used as a sugar donor. However, a good GlcNAc transferase activity was observed with a hexasaccharide [GlcAbeta1-4GlcNAcalpha1-4]_2-GlcAbeta1-4aMan (aMan, anhydromannose) as an acceptor, confirming the heparin chain polymerization activity.(4)The above observations seem to indicate that there are structural requirements or unreported intermediates necessary for the biosynthetic sorting mechanisms of chondroitin sulfate and heparin / heparan sulfate.

（1）以小鼠肥大细胞瘤微粒体组分为酶源，以UDP-GalNAc为糖供体，以合成的糖丝氨酸GlcAbeta 1 - 3Galbeta 1 - 3Galbeta 1 - 4Xylbeta 1-O-Ser为糖受体，观察到GalNAc转移。然而，发现该连锁是α连锁而不是β连锁。这与我们先前使用从胎牛血清纯化的酶制剂获得的观察结果一致。（2）以GlcAbeta 1 -3Gal（4-O-硫酸酯）beta1 - 3Galbeta 1 - 4Xylbeta 1-O-Ser作为糖受体时未观察到上述活性，表明硫酸酯基团抑制了α-GalNAc转移酶反应。(3)On另一方面，当在类似的孵育条件下进行测定时，除了使用UDP-GlcNAc作为糖供体之外，没有观察到肝素生物合成所预期的α-GlcNAc转移酶活性。然而，用六糖[GlcAbeta 1 - 4GlcNAcalpha 1 -4]_2-GlcAbeta 1 -4aMan（aMan，脱水甘露糖）作为受体观察到良好的GlcNAc转移酶活性，证实了肝素链聚合活性。（4）上述观察似乎表明，硫酸软骨素和肝素/硫酸乙酰肝素的生物合成分选机制需要结构要求或未报道的中间体。

项目成果

Kerstin Lidholt: "Assessment of glycosaminoglycan-protein linkage tetrasaccharides as acceptors for GalNAc-and GlcNAc-transferases from mouse mastocytoma" Glycoconjugate Journal. (印刷中). (1997)

Kerstin Lidholt：“评估糖胺聚糖-蛋白质连接四糖作为小鼠肥大细胞瘤的 GalNAc-和 GlcNAc-转移酶的受体”《糖结合杂志》（出版中）。