Sialidases catalyze the removal of \( \tilde \alpha \) glycosidically linked sialic acid residues from glycoproteins, glycolipids, and oligosaccharides, which is an initial step in the degradation of these glycocongugates. They demonstrate great variation in their expression during cell differentiation, cell growth, and malignant transformation, and have been shown to be intimately involved in many biological processes (Miyagi et al. 2004). Herein, four types of mammalian sialidase have been cloned and identified so far, and summarized briefly in terms of their properties and possible functions (see Table 1). Although the sequences of Neu1, Neu2, Neu3, and Neu4 are not particularly similar to those of bacterial and parasite sialidases, sequence alignment has revealed that they all contain several Asp boxes (-Ser-X-Asp-X-Gly-X-Thr-Trp-), and an Arg-Ileu-Pro sequence, conserved sequences found in sialidases from microorganisms.
KeywordsSialic Acid Sialic Acid Residue NEU1 Gene Sodium Metaperiodate Percoll Density Gradient Centrifugation
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