Abstract: The invention provides an oligosaccharide-fluorescent marker, and a preparation method and use thereof. The method includes reacting an oligosaccharide with a fluorescent agent in a solvent in the presence of a reducing agent to obtain the oligosaccharide-fluorescent marker. According to the oligosaccharide-fluorescent marker of the invention, an amino group in the fluorescent agent is subjected to a condensation reaction with a hemiacetal group at a reducing end of the oligosaccharide, to form an imine or Schiff base, and then the imine or Schiff base is reduced into a relatively stable secondary amine by using the reducing agent. In this way, the end of the oligosaccharide is fluorescently marked. The fluorescent group marked at the end has small influence on the biological activity of the oligosaccharide, and the marker has higher fluorescence intensity and is stable under physiological conditions.

Abstract: The invention provides a non-animal chondroitin sulfate oligosaccharide and a preparation method thereof. The method includes a one-step chemical procedure and an enzyme catalysis procedure that are orderly carried out, including: extracting Escherichia coli K4 polysaccharide, chemically removing the fructosyl group therefrom, and degrading with a chondroitin sulfate degrading enzyme to obtain a chondroitin oligosaccharide mixture; preparing chondroitin disaccharide to octasaccharide by separation by separation by a centrifugal ultrafiltration tube, Bio-Gel P-2 gel exclusion chromatography, and high performance liquid chromatography (HPLC); and enzymatically modifying the obtained products by 4-O-sulfation and 6-O-sulfation, to obtain chondroitin sulfate CS-A and CS-C oligosaccharides respectively.