中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | 1,3,4,6-tetra-O-acetyl-2-deoxy-2-trichloroacetamido-D-glucopyranose | 219693-02-4 | C16H20Cl3NO10 | 492.695 |
Ganglioside GQ1b ? is the most potent antagonist of the Myelin-associated glycoprotein (MAG) identified so far. For the efficient synthesis of the partial structure of GQ1b ? and derivatives thereof, a chemo-enzymatic strategy using the ?(2?3)-sialyltransferase ratST3Gal III (EC 2.4.99.6) was applied. Besides the natural substrates Gal? (1?3)GlcNAc (19) and Gal? (1?4)GlcNAc (20), the disaccharides Gal? (1?3)GalNTCA?-OSE (9), Gal? (1?3)GalNAc?-OSE (11), and Gal? (1?3)Gal?-OSE (14) were also tolerated by the enzyme and were transformed to the target structures in preparative scale.
Research over the past two decades has uncovered numerous biological roles for carbohydrates, e.g. in cell adhesion processes, signal transduction, malignant transformation, or viral and bacterial cell-surface recognition. Carbohydrates and structural analogues thereof are therefore considered as potential new leads. Although the chemical synthesis of carbohydrates is well established, the preparation of particular oligosaccharides still remains a costly and cumbersome challenge. A complementary approach to the chemical synthesis is the use of enzymatic methods. The transfer of monosaccharide moieties to natural substrates, catalyzed by glycosyltransferases, exhibits excellent chemo-, regio- and stereoselectivity. In addition, enzymatic glycosylations permit the synthesis of carbohydrate derivatives and even carbohydrate mimetics. Our results reveal a remarkable synthetic potential of fucosyltransferases VI (EC 2.4.1.65) and III (EC 2.4.1.65), and ? (2?3)-sialyltransferase ST3Gal III (EC 2.4.99.6). Their use for the preparative synthesis of oligosaccharides and derivatives as well as mimetics thereof is demonstrated.