Neuraminic Acid(redirected from sialidase)
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neuraminic acid[¦nu̇r·ə¦min·ik ′as·əd]
5-amino-3, 5-deoxy-D-glycero-n-galac-to-2-nonulosonic acid, a natural compound occurring as N- and O-acyl derivatives (sialic acids) in all the organs and tissues of animals and in certain microorganisms. The acyl derivatives of neuraminic acid (the most common of which are N-acetyl and N-glycolyl neuraminic acids) are constituents of natural glycolipids and glycoproteins, where they are bonded to monosaccharide radicals. The neuraminic acid radical is split off from the glycolipid and glycoprotein molecules under the action of the specific enzyme neuraminidase or dilute acids, thereby substantially altering the physicochemical and biological properties of the molecules. Certain pathological conditions (cancer, tuberculosis, mental disorders) induce a marked increase in the neuraminic acid content of fluids and tissues in the human body. In glycolipid form, neuraminic acid takes part in the fixation of certain viruses and neurotoxins in animal organisms. The biosynthesis of neuraminic acid is effected in the presence of hexosa-mine derivatives and pyruvic acid.