are a class of antibiotic drugs. They consist of a glycosylated cyclic or polycyclic nonribosomal peptide. Important glycopeptide antibiotics include vancomycin, teicoplanin, ramoplanin, and decaplanin. This class of drugs inhibits the synthesis of cell walls in susceptible microbes by inhibiting peptidoglycan synthesis. Glycopeptides exhibit a narrow spectrum of activity as principally effective against gram positive cocci. They are the last line of effective defense against MRSA and multiresistant enterococci for patients who are critically ill. At the beginning of the 90' there started a large scale research program for finding glycopeptide antibiotics with optimized properties. These studes resulted in the discovery of the hemi-synthetic compounds (1996 oritavancin) which have lower toxicity than vancomycin.

glycoprotein is a compound containing carbohydrate (or glycan) covalently linked to protein. The carbohydrate may be in a form of monosaccharide, disaccharide(s), oligosaccharide(s), polysaccharide(s), or their derivatives (e.g. sulfo- or phos-pho-substituted). One, a few, or many carbohydrate units may be present. There are two most common types of glycoproteins: O- and N-glycoproteins. In eukaryotes, the most prevalent type of O-linked glycosylation is the mucin-type glycosylation, where N-acetyl-D-galactosamine (GalNAc) is linked in an ?-anomeric configuration to the ?-hydroxyl group of either a serine or a threonine residue of the polypeptide. Other types of O-linked glycosylation include glycosaminoglycans, such as heparin and chondrotin sulfate, which are attached to the polypeptide chain through ?-linked xylose residues. An older and more prevalent type of glycosylation, N-linked glycosylation, is found in a wide range of organisms ranging from Archae to mammals and other eukaryotes. N-Glycosylation is a modification performed cotranslationally (during the translation of mRNA to protein) and is available to any secreted or membrane-bound protein containing the triplet amino acid sequence AsnXxxSer/Thr (where Xxx is any amino acid except Pro). An oligosaccharide is transferred to the amide side chain of Asn from a dolichol phosphate glycosyl donor, by the action of mem-brane-bound oligosaccharyl transferase in the endoplasmic reticulum (ER). The fully translated glycoprotein is then subject to glycan trimming and processing which is further elaborated in the ER and Golgi apparatus.