Carbohydrate–protein interactions are the intermolecular and intramolecular interactions between protein and carbohydrate moieties. These interactions form the basis of specific recognition of carbohydrates by lectins. Carbohydrates are important biopolymers and have a variety of functions. Often carbohydrates serve a function as a recognition element. That is, they are specifically recognized by other biomolecules. Proteins which bind carbohydrate structures are known as lectins. Compared to the study of protein–protein and protein–DNA interaction, it is relatively recent that scientists get to know the protein–carbohydrate binding.
Many of these interactions involved carbohydrates found at the cell surface, as part of a membrane glycoprotein or glycolipid. These interactions can play a role in cellular adhesion and other cellular recognition events. Intramolecular carbohydrate–protein interactions refer to interactions between glycan and polypeptide moieties in glycoproteins or the glycosylated proteins.