Oligosaccharides on bioactive peptides and proteins are known to have various effects on peptides and proteins, such as increasing stability and solubility, reducing antigenicity and controlling internal clearance. However, since glycoproteins have diverse oligosaccharides (glycoforms), the relationship between oligosaccharides and their functions is generally unclear. That is where we come in with our glycopeptide and glycoprotein synthetic technology for homogeneous oligosaccharides. Since our asparagine-linked oligosaccharides already have an Fmoc group, they can be used in solid phase peptide synthesis using the Fmoc method. This makes it possible to synthesize glycopeptides having specific and pure oligosaccharides. We can modify oligosaccharides with an bromoacetamide group at the reducing terminal. These oligosaccharides can be made to bond easily with the cystein residue in peptide and protein sequences.