Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

alpha-(2,3)-Sialylated biantennary and triantennary oligosaccharides were enzymatically prepared from pyridyl-2-amino-oligosaccharides with terminal Gal residues, using an alpha-(2,3)-specific trans-sialidase from Trypanosoma cruzi (Lee, K. B., and Lee, Y. C. (1994) Anal. Biochem. 216, 358-364). From the pyridyl-2-amino-derivatives of neutral and alpha-(2,6)-monosialylated biantennary oligosaccharides from human fibrinogen, 5 different sialyl biantennary oligosaccharides were obtained. From two different asialo-triantennary oligosaccharides from fetuin, 35 sialyl oligosaccharides were obtained. The trans-sialidase transferred sialic acids effectively and indiscriminately to different galactosyl residues in the different positions on the substrates. Since the starting materials are neutral oligosaccharide of established structure, and the only alpha-(2,3)-sialyl residues are added to the nonreducing Gal terminal residues, the structures of these oligosaccharides could be identified unambiguously by using the three-dimensional mapping technique (Takahashi, N., Nakagawa, H., Fujikawa, K., Kawamura, Y., and Tomiya, N. (1995) Anal. Biochem. 226, 139-146.) in combinations with strategic digestion with beta-galactosidase, beta-N-hexosaminidase, and sialidase L.
 ...
PMID:Enzymatic sialylation of N-linked oligosaccharides using an alpha-(2,3)-specific trans-sialidase from Trypanosoma cruzi: structural identification using a three-dimensional elution mapping technique. 750 27

Sialidase L releases 2,7-anhydro-NeuAc from sialoglycoconjugates (Li, Y.-T., Nakagawa, H., Ross, S. A., Hansson, G., and Li, S.-C. (1990) J. Biol. Chem. 265, 21629-21633). This enzyme has been purified more than 10,000-fold from Macrobdella leech. The final preparation gives a single protein band on SDS-polyacrylamide gel electrophoresis with the molecular mass of 84 kDa. The pI is determined to be 6.0 using isoelectric focusing. With 4-methylumbelliferyl-alpha-NeuAc as substrate, the pH optimum is between pH 5.5-7.0. Unlike regular sialidases, sialidase L is not inhibited by 2-deoxy-2,3-dehydro-NeuAc. Two of the seven tryptic peptides derived from sialidase L contain the consensus repeat S-X-D-X-G-X-T-W that has been found in the regular sialidases. Among various sialoglycoconjugates tested, sialidase L cleaves only the NeuAc alpha 2-->3Gal linkage. NeuAc alpha 2-->6Gal, NeuAc alpha 2-->6GalNAc, NeuAc alpha 2-->6GlcNAc, NeuAc alpha 2-->8-NeuAc, and NeuAc alpha 2-->9NeuAc linkages are not hydrolyzed. At pH 7.0, sialidase L and Clostridial sialidase release 46 and 92% of sialic acid, respectively, from bovine fetuin, indicating that sialidase L selectively cleaves NeuAc alpha 2-->3Gal linkages in fetuin. Sialidase L is the first sialidase found to exhibit a strict specificity toward the hydrolysis of the NeuAc alpha 2-->3Gal linkage, and it should become useful for the selective cleavage of NeuAc alpha 2-->3Gal linkages in sialoglycoconjugates without destroying other sialosyl linkages.
 ...
PMID:Purification and characterization of sialidase L, a NeuAc alpha 2-->3Gal-specific sialidase. 803 34

Sialidase L is a NeuAcalpha2-->3Gal linkage-specific sialidase that releases 2,7-anhydro-NeuAc instead of NeuAc from sialoglycoconjugates (Chou, M.-Y., Li, S.-C., Kiso, M., Hasegawa, A., and Li, Y.-T.(1994) J. Biol. Chem. 269, 18821-18826). A 2. 5-kilobase cDNA of sialidase L was cloned by a combination of methods based on polymerase chain reactions. The composite cDNA sequence reveals an open reading frame coding for 762 amino acids, including a putative 28-residue signal peptide at the N terminus that is similar to the signal sequence of the Clostridium septicum sialidase. The result suggests that sialidase L is a secretory enzyme. The coding sequence excluding the putative signal peptide of sialidase L was overexpressed in Escherichia coli. The purified recombinant enzyme was characterized to be as active as the enzyme isolated from the leech. It also possessed the strict NeuAcalpha2-->3Gal linkage specificity and released the unique cleavage product, 2,7-anhydro-NeuAc from sialoglycoconjugates. The deduced amino acid sequence of sialidase L exhibits little similarity with other reported sialidases. However, sialidase L contains a conserved "FRIP region" and four repeating "Asp box" motifs that align well with the corresponding positions of bacterial sialidases. The predicted beta-strand structures near the conserved motifs of sialidase L are similar to those of Salmonella typhimurium sialidase. Several conserved single amino acid residues of bacterial sialidases, including those known to be involved in the active site of Salmonella enzyme, are conserved in the deduced amino acid sequence of sialidase L. This observation suggests that part of the catalytic mechanism of sialidase L may be similar to the ordinary sialidase.
 ...
PMID:Cloning and expression of sialidase L, a NeuAcalpha2-->3Gal-specific sialidase from the leech, Macrobdella decora. 870 1

Functional monomeric 83 kDa sialidase L, a NeuAcalpha2-->3Gal-specific sialidase from Macrobdella leech, was expressed in Escherichia coli and readily crystallized by a macroseeding technique. The crystal belongs to space group P1 with unit-cell parameters a = 46.4, b = 69.3, c = 72.5 A, alpha = 113.5, beta = 95.4 and gamma = 107.3 degrees. There is one molecule per unit cell, giving a Vm = 2.4 A3 Da-1 and a solvent content of 40%. Native and mercury-derivative data sets were collected to 2.0 A resolution. Threading and molecular-replacement calculations confirmed the existence of a bacterial sialidase-like domain.
 ...
PMID:Crystallization and preliminary X-ray studies of sialidase L from the leech Macrobdella decora. 976 28

Sialidases are enzymes essential for numerous organisms including humans. Hydrolytic sialidases (EC 3.2.1.18), trans-sialidases and anhydrosialidases (intramolecular trans-sialidases, EC 4.2.2.15) are glycoside hydrolase enzymes that cleave the glycosidic linkage and release sialic acid residues from sialyl substrates. The paper summarizes diverse sialidases present in the human body and their potential impact on development of antiviral compounds - inhibitors of viral neuraminidases. It includes a brief overview of catalytic mechanisms of action of sialidases and describes the origin of sialidases in the human body. This is followed by description of the structure and function of sialidase families with a special focus on the GH33 and GH34 families. Various effects of sialidases on human body are also briefly described. Modulation of sialidase activity may be considered a useful tool for effective treatment of various diseases. In some cases, it is desired to completely suppress the activity of sialidases by suitable inhibitors. Specific sialidase inhibitors are useful for the treatment of influenza, epilepsy, Alzheimer's disease, diabetes, different types of cancer, or heart defects. Challenges and future directions are shortly depicted in the final part of the paper.
 ...
PMID:Diversity of sialidases found in the human body - A review. 3194 39