The present application discloses novel glycoproteins and a related glycosylcarbamoylation methodology suitable for the preparation of glycopeptides (in particular glycoproteins and glycosylated cells), as well as the use of such glycoproteins in medicine, e.g. as pharmaceuticals and diagnostics or in diagnostic kits. A method for the preparation of a carbohydrate-peptide conjugate includes reacting a cyclic carbamate with a peptide which has at least one primary amino group.