Molecular Design of Fluorescent Labeled Glycosides as Acceptor Substrates for Sialyltransferases

作者：Ogata Makoto^*; Obara Takakiyo; Chuma Yasushi; Murata Takeomi; Park Enoch Y; Usui Taichi

来源：Bioscience Biotechnology and Biochemistry, 2010, 74(11): 2287-2292.

DOI：10.1271/bbb.100505

• sialyltransferase
• enzyme assay
• chemoenzymatic synthesis
• substrate specificity
• bi-antennary oligosaccharide

A series of dansyl-labeled glycosides with di-, tetra-, and hexasaccharides carrying the terminal N-acetyllactosamine (LacNAc) sequence were synthesized as acceptor substrates for alpha 2,6- and alpha 2,3-sialyltransferases. As an alternative design, dansyl-labeled LacNAc glycoside carrying a long-spacer linked glycan was engineered by replacement of the LacNAc or lactose units with an alkyl chain. In addition, we designed a dansyl-labeled bi-antennary LacNAc glycoside as an N-linked oligosaccharide mimetic, such as asialo-alpha(1)-acid glycoprotein. The kinetic parameters for the transfer reaction of synthesized dansyl-labeled glycosides by sialyltransferases were determined by the fluorescent HPLC method. The catalytic efficiencies (V-max/K-m) of acceptor substrates carrying the terminal LacNAc sequence with various length glycans in the array for alpha 2,6- and alpha 2,3-sialyltransferases decreased in a glycan length-dependent manner. Furthermore, of the acceptor substrates tested, dansyl-labeled bi-antennary LacNAt glycoside displayed the most favorable K-m value for alpha 2,6- and alpha 2,3-sialyltransferases.

• 出版日期2010-11