Regioselective α(2→3)-Sialylation of Le^X and Le^a by Sialidase-Catalyzed Transglycosylation

Abstract

Considerable effort has been devoted to the development of new methods for α-selective sialylation due to the growing importance of the synthetic sialoglycoconjugates in glycobiology³. The synthesis of α-sialoside has been establised by chemical routes,⁴ which often involve many steps and are complicated. The promising chemoenzymatic procedure through the use of sialyltransferases has already become a preparative technique.⁵ However, laborious isolation and the pronounced acceptor specificity of the transferases limit their synthetic potential. Recently, a novel procedure for α-sialylation has been reported, which uses sialosides of synthetic substrate as donors and is catalyzed by sialidase in place of sialyltransferase. Thiem et a1.⁶ have reported the enzymatic synthesis of α(2→6)-linked sialyl galactose, glucose, lactose and lactosamine in preference to the corresponding α(2→3)-linked derivatives employing sialidase from vibrio cholerae, while Ajisaka et al.⁷ have synthesized α(2→3)-linked sialyl lactose and lactosamine with sialidase from new castle disease virus.

1. Synthetic studies on sialoglycoconjugates, Part 101. For Part 100, see H. Ito, H. Ishida, M. Kiso and A. Hasegawa, Carbohydr. Res., 306, 1 (1998).

Notes

1. Synthetic studies on sialoglycoconjugates, Part 101. For Part 100, see H. Ito, H. Ishida, M. Kiso and A. Hasegawa, Carbohydr. Res., 306, 1 (1998).