. . "N-acetylneuraminate, the most ubiquitous species amongst the sialic acids, is widely distributed in the animal kingdom as a component of oligosaccharides, glycoproteins, and glycolipids. N-acetylneuraminate carries out various biological functions by acting as receptors for microorganisms, viruses, toxins, and hormones, by masking receptors, and by regulation of the immune system. N-acetylneuraminic acid is the predominant form of sialic acid present in humans. It can be found as a terminal sugar on a wide range of surface glycoconjugates |CITS: [11841250]|. This acid is present in sialoconjugates as the α-anomer |CITS: [18063573]|. A number of bacteria that can colonize humans make use of N-acetylneuraminic acid as a nutrient source. In addition, some pathogens such as Haemophilus influenzae use for sialic acid in an immune evasion mechanism by adding N-acetylneuraminic acid to their lipopolysaccharide |CITS: [12180977][10447878]|, which provides increased survival in human serum. Most of these organisms are not capable of synthesizing N-acetylneuraminic acid and import it into the cells |CITS: [16262798]| after conversion (either spontaneous or enzymatic) to the β-anomer |CITS: [18063573]| ."^^ . . . "N-acetylneuraminate"^^ . "sialic acid"^^ . "Neu5Ac"^^ . "NANA"^^ . "5-acetamido-3,5-dideoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid"^^ . "N-acetylneuraminic acid"^^ . "sialate"^^ . "O-sialic acid"^^ . "N-acetylneuraminate"^^ . "5-acetamido-3,5-dideoxy-D-glycero-D-galacto-2-nonulosonic acid"^^ . . "N-acetylneuraminate"^^ .