GM1 consists of a sialic acid-containing oligosaccharide covalently attached to a ceramide lipid. Glycoproteins are proteins which contain oligosaccharide chains (glycans) covalently attached to amino acid side-chains. Sialyltransferases are enzymes that transfer sialic acid to nascent oligosaccharide. Acarbose is an oligosaccharide, whereas miglitol resembles a monosaccharide. The result of glycosyl transfer can be a carbohydrate, glycoside, oligosaccharide, or a polysaccharide. These interactions are further tuned by the glycan (oligosaccharide) at position CH2-84.4 of IgG. PNGase F catalyzes the cleavage of an internal glycoside bond in an oligosaccharide. The glycone can consist of a single sugar group (monosaccharide) or several sugar groups (oligosaccharide). The lipopolysaccharide consists of three moieties&colon; lipid A, a core oligosaccharide, and an "O"-polysaccharide (O-antigen). It contains vitamin B1, B2, B6, folic acid, dietary fiber, oligosaccharide, cysteine, arginine and glutamine. The OB-fold is a small structural motif originally named for its oligonucleotide/oligosaccharide binding properties. It differs from endogenous erythropoietin (EPO) by containing two more N-linked oligosaccharide chains. The outer core oligosaccharide chain varies depending on the bacterial strain. This adds fucose to the oligosaccharide precursor in a different position from the FUT3 enzyme. The head of the oligosaccharide serves as a binding partner in receptor activity.