Carbohydrates linked to amino acids and proteins

NATURAL-ABUNDANCE, 13C-NUCLEAR MAGNETIC RESONANCE-SPECTRAL STUDIES OF CARBOHYDRATES LINKED TO AMINO ACIDS AND PROTEINS... 

By far the majority of carbohydrate material in nature occurs in the form of polysaccharides. By our definition, polysaccharides include not only those substances composed only of glycosidically linked sugar residues but also molecules that contain polymeric saccharide structures linked via covalent bonds to amino acids, peptides, proteins, lipids, and other structures. 

Carbohydrates constitute one the of most complex structures occurring in nature (with nucleic acids and proteins) due to i) the monosaccharide diversity, ii) the type of linkage and iii) the nature of carbohydrate-linked molecules. As a result, GHs present a wide range of activities, which have necessitated the creation of a specific classification more explicit than the lUB Enzyme Nomenclature. In 1998, the Carbohydrate-Active Enzymes (CAZy) database was created, gathering glycosidases in famiUes based on amino-acid sequence and protein structures similarities. ... 

Indirectly, the Na" /K -ATPase provides the energy for the active transport of amino acids and some carbohydrates into cells. The plasma membrane contains specific proteins that mediate the transport of these molecules in a manner that is obligatorily linked to the cotransport of... 

---