Production of sialyloligosaccharides by trans-sialidase catalyzed reaction using fetuin as a sialic acid donor

摘要

Typically, alpha-2,3-sialylactose is used as the sialic acid donor in trans-sialidase catalyzed reaction. However, due to limitations such as reversibility and cost, alternative sialic acid donors are needed. Here we show tht fetuin, a glycoprotein containing abundant sialic acids at the ends of it oligosaccharides, can be used as a sialic acid donor in trans-sialidase catalyzed reaction. Among 166 nmol of total sialic acid in milligrams fetuin, 125 nmol of sialic acid was was consumed for the trans-sialidase reaction. The trans-sialidase reaction using fetuin was reversible. The sialyl transfer rate of fetuin to Galbeta(1,4)GlcNAc ws similar to that of alpha-2,3-sialylallactose and approximately 30-40 times greater than that of 4-methylumbelliferyl-alpha-sialic acid. trans-Sialidase reaction was performed using 200 mg of fetuin and 34 mg of lactose as a donor and an accpetor, respectively, and 8 mg of product, i.e, alpha-2,3-sialyllactose, was purified by gel filtration column. To simplify the purification step, trans-sialidase reaction was carried out by submerging and stirring a dialysis bag containing fetuin and trans-sialidase into a lactose solution.