The present invention relate to molecular building blocks of the formula R1-A-R3, wherein A is a carbohydrate derivative and R1 is hydrogen or an amino protecting group and R3 is either a hydroxyl, a protecting group or a leaving group. The building blocks are capable of attaching carbohydrate derivatives and fatty acid residues to amino acids. By use of these carbohydrate building blocks, means for providing proteins and peptides with the additional functionalities of carbohydrates and of fatty acid residues and particularly to provide peptides and proteins with the combined functionalities of fatty acids and carbohydrates are provided.
