Efficient sialylation on azidododecyl lactosides by using B16 melanoma cells

Lactoside primers (dodecyl lactoside derivatives) resemble intermediates in the biosynthetic pathway of glycolipids and, therefore, act as substrates for cellular enzyme-catalyzed glycosylation. To establish the optimal condition for the bioproduction of a large amount of valuable materials containing GM3-type oligosaccharides, two kinds of lactoside primers having the azido group in different positions were synthesized and introduced into B16 melanoma cells. The saccharide chains of both primers were elongated by cells to give GM3-type oligosaccharide derivatives, which were released to the culture medium. The amount of glycosylated product from newly synthesized 2-azidododecyl beta-lactoside (primer II) was almost twice that from 12-azidododecyl beta-lactoside (primer I). The effects of seeded cell number, primer concentration, and length of incubation time on the glycosylation efficiency were also investigated. The results showed that the higher the seeded cell number, the larger the amount of sialylated products obtained. The optimum concentrations of primers I and II were found to be 200 and 100 microM, respectively. Above these concentrations, productivity and cell viability decreased. As regards the length of incubation time, the sialylated products increased linearly until 48 h, but productivity did not advance thereafter. These results represent the optimal conditions that are necessary for the mass production of GM3-type oligosaccharide using azidododecyl lactoside primers and B16 cells.