Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.53 (sialidase)
2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We compared sialidase (neuraminidase; EC 3.2.1.18) from Vibrio cholerae, Clostridium perfringens, and Arthrobacter ureafaciens, seeking to improve the electrophoretic separation of the liver and bone isoenzymes of alkaline phosphatase (EC 3.1.3.1) on cellulose acetate membranes. Resolution is decisively determined by the type and activity of sialidase used in the preincubation of serum sample. Sialidase from Arthrobacter ureafaciens is not suited for this method. For optimal separation of the two isoenzymes we recommend the use of sialidase from Vibrio cholerae, determination of its activity with a standard procedure such as described here (mucin or sialyl lactose as substrates), and a final concentration of sialidase activity of 2.0 or 2.9 U/L (measured with mucin or sialyl lactose) in the incubation mixture.
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PMID:Sialidase from different sources compared for electrophoretically separating serum alkaline phosphatase fractions from liver and bone. 277 24

Normal and adenomatous colonic tissues from children with Gardner's syndrome were compared to analogous tissues from adults bearing adenomatous polyps using mucin histochemical and lectin-binding techniques. Adenomatous tissue from children exhibited general morphological similarity to its adult homologue, but showed less dysplasia. Its goblet cells stained weaker for mucins and the lectins Dolichos biflorus agglutinin (DBA) and peanut agglutinin (PNA). This suggested underglycosylation of side chains of mucins in these childhood adenomas. The weak DBA and relatively intense sulfomucin staining in these adenomas suggested that they arose from deep crypt cells. Adult adenomas shared certain histochemical properties with carcinomas, namely, increased affinity for periodic acid-Schiff (PAS) and focally for PNA. There is evidence based on the effects of saponification and sialidase treatments that the weak initial PAS reaction in normal and adenomatous colonic goblet cells from both age groups results from substituents on sialic acid and, in the case of normal colon from children, on other monosaccharides as well. Finally, there was a frequent lack of parellelism between PAS and lectin staining suggesting that different groups within the sugars are responsible for reactivity with those compounds.
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PMID:Histochemical and morphological analysis of colonic epithelium from children with Gardner's syndrome and adults bearing adenomatous polyps. 282 93

In this study we show that the adhesion to mucus of the enterotoxigenic Escherichia coli strains responsible for diarrhea in calves involves a bacterium-mucin recognition phenomenon in which the bacterial pili and specific mucus receptors carried by the glycoproteins (2,000 to 400 kilodalton) play a major role. An adhesion maximum was observed at a pH of less than 6 (4.75 to 5.25). The sialic acids and galactose appeared to be at least partly responsible for the attachment of K99 pili, whereas F41 pili preferentially recognized desialylated receptors. The attachment of different strains of E. coli characterized by the presence of the three main pili, K99, F41, and FY, known to be responsible for the binding of enterotoxigenic E. coli to the intestinal epithelium of the calf, was studied using Scatchard and Hill analyses. The attachment mechanism of bacteria carrying K99 pili showed positive cooperativity. FY and F41 pili recognized independent receptor sites, the first on sialylated mucus and the second on sialidase-treated mucus. Moreover, F41 pili were found to bind the native mucus according to a negative cooperativity phenomenon. Finally, the recognition sites carried by bacterial pilins may be saturated by some animal glycoprotein glycans which are therefore adhesion inhibitors.
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PMID:Pilus-mediated binding of bovine enterotoxigenic Escherichia coli to calf small intestinal mucins. 288 23

Gastric and intestinal phenotypic expression in 37 surgically obtained primary signet ring cell carcinomas, five of their metastases to lymph nodes, and three signet ring cell carcinomas transplanted into nude mice were determined by biochemical, mucin, histochemical, and ultrastructural studies. Crude extracts of cancer tissues were used for measurements of pepsinogen isozymes, sucrase, aminopeptidase (microsomal), and alkaline phosphatase. Histochemical staining of mucin by paradoxical concanavalin A, the galactose oxidase-Schiff sequence and sialidase-galactose oxidase-Schiff, and the periodate-borohydride technique/potassium hydroxide/periodic acid-Schiff procedure was performed. The procedures allowed clear definition of pyloric gland, surface mucous, small and large intestinal goblet, and intestinal absorptive cell types. Of 40 specimens examined, 19 consisted entirely of gastric-type cells, and three entirely of intestinal-type cells. The others consisted of mixtures of gastric and intestinal-type cells. The observed high incidence of intestinal-type cells in signet ring cell carcinomas suggested that intestinal-type cells develop independently from intestinal metaplasia within signet ring cell carcinomas (diffuse-type gastric cancers), which probably originate from nonmetaplastic gastric mucosa.
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PMID:Gastric and intestinal phenotypic expressions of human signet ring cell carcinomas revealed by their biochemistry, mucin histochemistry, and ultrastructure. 301

Sialate 9(4)-O-acetylesterases (EC 3.1.1.53) have been isolated from equine liver, bovine brain and influenza C virus. In this latter case, the esterase represents the receptor-destroying enzyme of the virus. The kinetic properties of these enzymes were determined with Neu5,9Ac2 and in part with 4-methylumbelliferyl acetate and Neu5,9Ac2-lactose. The Km values vary between 0.13 and 24 mM and the Vmax values from 0.55 to 11 U/mg of protein. The pH optima are in the range of 7.4-8.5, the molecular masses at 56,500 and 88,000 Da. In addition to a fast hydrolysis found for aromatic acetates, such as 4-methylumbelliferyl acetate or 4-nitrophenyl acetate, N-acetyl-9-O-acetylneuraminic acid is de-O-acetylated at the highest relative rate. Other substituents at the 9-position, such as lactoyl residues, or acetyl groups at other positions within the side chain are not hydrolyzed. Neu4,5Ac2, however, is a substrate for all 3 enzymes. The hydrolysis rates of this ester function, which renders sialic acids resistant to the action of sialidases, vary from 3 to 100% relative to Neu5,9Ac2. Whereas Neu5,9Ac2-lactose is hydrolyzed by the bovine and viral esterases, other O-acetylated sialic acids in glycoconjugates are only attacked by the enzyme from influenza C virus and not by that from bovine brain. The esterase from horse liver also releases 4-O-acetyl groups from equine submandibular gland mucin. By incubation with appropriate substrates and inhibition studies, carboxylesterase, amidase and choline esterase activities were excluded, as well as the cleavage of other acyls, e.g., butyryl groups. Thus, the enzymes investigated belong to the acetylesterases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sialate O-acetylesterases: key enzymes in sialic acid catabolism. 314 20

Mucins were extracted from human amniotic fluid in the presence of 45% vol. phenol and separated from the bulk of smaller-sized glycoproteins by exclusion on Sephacryl S400. The mucin-fraction FW, which still contained a minute proportion of mannose, strongly expressed oncofetal antigens recognized by monoclonal antibodies C 50, NS 19-9, OC 125, Leu M1, 49 H 8, and 115 C 2. The structures of the respective mucin-linked saccharides responsible for Ca 50-, Ca 19-9-, and Lea-related antigenic activities were analyzed before or after reductive beta-elimination from sialylglycoproteins, and purification of the derived alditols by gel-permeation chromatography on Bio-Gel P-4 or high performance liquid chromatography. Two ubiquitous (FW2, FW3) and three novel oligosaccharide alditols (FW5) were characterized by f.a.b.- and e.i.-m.s., combined with methylation analysis and chromium trioxide oxidation. The OC 125 epitope on mucin-carried O-glycans was destroyed during reductive cleavage of the saccharides, indicating a conformational involvement of the reducing terminal residue and its mode of conjugation to the protein. Exoglycosidase treatment of the mucin-bound antigen revealed that the epitope structure of OC 125 includes terminal beta-D-galactosyl groups, and terminal sialyl groups that are almost inaccessible to Vibrio cholerae sialidase digestion.
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PMID:Structural studies on oncofetal carbohydrate antigens (Ca 19-9, Ca 50, and Ca 125) carried by O-linked sialyloligosaccharides on human amniotic mucins. 319 9

An esterase was isolated from influenza C virus with a specific activity from 1.7-5 U/mg protein, and its substrate specificity was tested with various naturally occurring O-acylated sialic acids, synthetic carbohydrate acetates, and other esters. The enzyme hydrolyses only acetic acid esters at significant rates. The non-natural substrates 4-methyl-umbelliferyl acetate, 4-nitrophenyl acetate, and alpha-naphthyl acetate are cleaved at highest hydrolysis rates, followed by the natural substrate N-acetyl-9-O-acetylneuraminic acid. The esterase also acts on N-glycoloyl-9-O-acetylneuraminic acid and, much slower, on N-acetyl-4-O-acetylneuraminic acid; N-acetyl-7-O-acetylneuraminic acid is not hydrolysed. 2-Deoxy-2,3-didehydro-N-acetyl-9-O-acetylneuraminic acid is also a substrate for this enzyme, however, 6-O-acetylated N-acetylmannosamine and glucose are not. Esterification of the carboxyl function of sialic acids strongly reduces or prevents esterase action on O-acetyl groups. The carboxyl ester is not hydrolysed. The relative cleavage rates also depend on the type of the non-sialic acid part of the molecule. N-Acetyl-9-O-acetylneuraminic acid as component of sialyllactose and rat serum glycoprotein shows hydrolysis rates close to the free form of this sugar, while acetyl ester groups of bovine submandibular gland mucin and rat erythrocytes are hydrolysed at slower rates. Gangliosides and 4-O-acetylated glycoproteins are no substrates for the purified enzyme. A slow hydrolysis is observed by incubation of 9-O-acetylated GD1a with intact influenza C viruses. As other natural acetyl esters (acetyl-CoA and acetylthiocholine iodide) are not hydrolysed, the enzyme can be classified as sialate 9(4)-O-acetylesterase (EC 3.1.1.53).
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PMID:Isolation and characterization of sialate 9(4)-O-acetylesterase from influenza C virus. 324 42

The synthesis and intracellular sorting of the interleukin-2 (IL-2) receptor were studied with a line of mutant Chinese hamster ovary (CHO) cells with a reversible defect in protein O glycosylation. Under normal culture conditions the mutant ldlD cannot add N-acetylgalactosamine (Ga1NAc) to proteins. Ga1NAc is the first sugar of mucin-type O-linked oligosaccharides attached to protein. This O-glycosylation defect is rapidly corrected when Ga1NAc is added to the culture mediu. An expression vector for the p55 human IL-2 receptor was transfected into wild-type CHO and ldlD cells and the structure, stability, and cell surface expression of the receptor were examined by immunoprecipitation and antibody-binding assays. Essentially all of the mature form of the normally glycosylated IL-2 receptor in both wild-type CHO cells and ldlD cells incubated with Ga1NAc was expressed on the cell surface. The stability of O-linked carbohydrate-deficient (Od) IL-2 receptors (in ldlD cells without Ga1NAc) was normal; however, missorting of the Od receptors resulted in very little cell surface expression. The sialidase sensitivity and endoglycosidase H resistance of mature Od IL-2 receptors suggest that Od receptor missorting occurred in or beyond the trans Golgi apparatus. The abnormal sorting of the Od IL-2 receptor is compared with the O-glycosylation dependence of the surface expression and stability of the low-density lipoprotein receptor, decay-accelerating factor, and the major antigen envelope protein of Epstein-Barr virus.
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PMID:Abnormal intracellular sorting of O-linked carbohydrate-deficient interleukin-2 receptors. 326 79

1. The activities of enzymes degrading human colonic mucin were examined in faecal specimens from healthy subjects and patients with inflammatory bowel disease. 2. The activity of sialidase was measured using a new physiological substrate related to mucus glycoproteins. In addition, acylneuraminate pyruvate-lyase (N-acetylneuraminate lyase; EC 4.1.3.3.) and a novel O-acetylsialic acid esterase (sialate O-acetylesterase; EC 3.1.1.53) were detected. 3. The O-acetylsialic acid esterase activity was readily detectable in partially purified fractions after Sephadex G-100 chromatography. 4. Patients with inflammatory bowel disease showed significant increases in acylneuraminate pyruvate-lyase and proteinase activity but sialidase activity did not differ from normal. The activity of these enzymes in neutrophils could not account for the differences observed.
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PMID:Degradation by bacterial enzymes of colonic mucus from normal subjects and patients with inflammatory bowel disease: the role of sialic acid metabolism and the detection of a novel O-acetylsialic acid esterase. 333 53

A lectin isolated from Rana catesbeiana eggs preferentially agglutinates a large variety of human and animal tumor cells but not normal red blood cells, lymphocytes, or fibroblasts. The phenomenon correlates with a higher binding activity of the lectin with tumor cells. Chemical and physical analysis of the purified lectin indicates that the lectin is a low molecular weight basic polypeptide with five intrachain disulfide bonds. Its agglutination of tumor cells was abolished by blocking the amino group. The lectin strongly binds with a large variety of tumor cells but binds only minimally with fibroblasts, lymphocytes, and erythrocytes. Tumor cell agglutination induced by this lectin was strongly inhibited by submaxillary mucin, to a lesser degree by fetuin and keratan sulfate, and not at all by less-sialylated glycoproteins, such as transferrin. Inhibition by mucin or fetuin was greatly reduced by desialylation of glycoprotein with sialidase. Treatment of tumor cells with sialidase greatly reduced the lectin-dependent agglutination, and the sialidase-dependent reduction of tumor cell agglutination was inhibited by the sialidase inhibitor 2,3-dehydro-2-deoxy-N-acetylneuraminic acid. However, tumor cell agglutination was not inhibited by chondroitin sulfates or hyaluronic acid. Thus, the lectin-dependent tumor cell agglutination is due to a high density of sialic acid at the cell surface. The receptor glycoprotein that interacts with this lectin was demonstrated in the detergent-insoluble fraction of a variety of tumor cells by sodium dodecyl sulfate:polyacrylamide gel electrophoresis, followed by Western blotting with lectin and anti-lectin antibodies. The presence of a common high molecular weight lectin-binding glycoprotein in various tumor cells was demonstrated.
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PMID:Isolation and characterization of Rana catesbeiana lectin and demonstration of the lectin-binding glycoprotein of rodent and human tumor cell membranes. 349 12


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