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)

Mucolipidosis II is a severe inherited lysosomal storage disease characterized by profound psychomotor retardation, severe Hurler-like skeletal changes and normal urinary mucopolysaccharide excretion. Mucolipidosis II is a related disorder distinguished by its milder course, milder to absent mental retardation and survival to adult life. Cultivated fibroblasts from patients with both of these disorders display large inclusions on phase microscopy and reduced levels of many acid hydrolases. However, culture medium fibroblasts out the body fluids of affected patients show enormously elevated levels of these hydrolases. The lysosomal enzyme activities in serum, leukocytes, fibroblasts extracts and culture medium from seven patients with mucolipidosis II are similar to those found in four cases of mucolipidosis III. The findings of excessive excretion of sialyl-oligosaccharide in urine and of increased level of sialic acid compounds in cultured fibroblasts associated with a sialidase deficiency in leukocytes, fibroblasts and serum are discussed.
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PMID:[Mucolipidosis. biologic characteristics (author's transl)]. 11 47

beta-Glucosidase-stimulating proteins have been purified from human brain. One of these proteins also activated oligosaccharide sialidase activity in fibroblasts from galactosialidosis and sialidosis patients and in control cells but was not able to stimulate residual sialidase from I-cell disease fibroblasts. Activation was observed with either sialyl-oligosaccharides and -glycoproteins or the artificial substrate MU-NANA. The activator did not stimulate ganglioside sialidase from control and mucolipidosis IV fibroblasts. Column chromatography, polyacrylamide electrophoresis or desialylation treatment of the activator did not achieve separation of the stimulating abilities toward beta-glucosidase and sialidase.
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PMID:An activator protein of oligosaccharide sialidase. 312 50

Cultured fibroblasts from patients with the lysosomal storage disease, mucolipidosis II, produce complex glycosylated lysosomal enzymes which are preferentially excreted presumably due to the absence of specific phosphomannosyl recognition residues needed for intracellular retention. Complex glycosylated hydrolases are also produced by fibroblasts from patients with mucolipidosis I but an abnormal excretion is not apparent in this disorder. Intra- and extracellular distribution, lectin binding, and specific endocytosis were criteria used to compared the properties of intra- and extracellular beta-hexosaminidase derived from mucolipidosis I and normal fibroblast cultures. Mucolipidosis I fibroblasts did not hyperexcrete beta-hexosaminidase when maintained in serum-free medium. Using the specificity of ricin binding to terminal galactosyl residues, the most galactosylated forms of the enzyme derived from mucolipidosis I cell extracts and culture fluids were found in the mucolipidosis I cell extracts (50% of total enzyme). Mucolipidosis I-excreted beta-hexosaminidase which was eluted from ricin-120-Sepharose, was a high-uptake form in endocytosis experiments while unbound enzyme was a low-uptake form. These data suggest that beta-hexosaminidase molecules contained phosphomannosyl residues necessary for receptor-mediated endocytosis as well as galactosyl residues on the same molecule. The co-existence of complex chains with high-mannose chains did not interfere with the phosphomannose-mediated endocytosis of beta-hexosaminidase nor with the retention of endogenous enzyme. We can speculate that since complex oligosaccharide chains in the mucolipidosis I cellular enzyme persist due to a sialidase deficiency, more extensive sialylation of cellular enzyme in normal fibroblasts probably occurs at some point during post-translational processing. However, the presence of sialidase in normal cells initiates complex chain trimming in the lysosomes resulting in a less glycosylated end product.
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PMID:Effect of the co-existence of galactosyl and phosphomannosyl residues on beta-hexosaminidase on the processing and transport of the enzyme in mucolipidosis I fibroblasts. 622 17

Assay conditions were studied for eight lysosomal enzymes in lymphoblastoid cell lines transformed by Epstein-Barr virus. The transformed lymphoblastoid cells retained all eight enzyme activities, though the levels sometimes differed from those in the peripheral lymphocytes or granulocytes. The levels of these eight lysosomal enzymes were measured in lymphoblastoid cells from 11 patients with hereditary lysosomal storage diseases--GMI-gangliosidosis, a variant of beta-galactosidase deficiency (sialidase deficiency with a partial beta-galactosidase deficiency), Tay-Sachs disease, Gaucher disease, Hurler syndrome, Scheie syndrome and I-cell disease--and from 20 of their obligate heterozygotes. No activity of enzymes that were deficient in the respective disease, except I-cell disease, was detected in the lymphoblastoid cells from the patient. In I-cell disease, the cells showed lower levels of some enzyme activities. beta-D-Galactosidase activity from heterozygotes of the patient with GMI-gangliosidosis and alpha-L-iduronidase activity from heterozygotes of the patient with Hurler syndrome were in carrier range. On sephadex G-150 gel filtration, beta-D-galactosidase in control material gave two peaks (I and II). In GMI-gangliosidosis, peak II was absent and peak I was markedly diminished. Peak II in the heterozygotes was smaller than that of control. On DEAE cellulose column chromatography of hexosaminidase, two major isoenzymes (hexosaminidase A and B) were detected in control. However, hexosaminidase A was not detected in Tay-Sachs disease, and the ratios of hexosaminidase (Hex) A/Hex B in the parents were lower than those in control.
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PMID:Lymphoblastoid cell lines, transformed by Epstein-Barr virus, in the enzymatic study of hereditary lysosomal storage diseases. 627 59

Ten enzymes, all known to be glycoproteins, were examined by electrophoresis or gel isoelectric focusing in 12 different patients with primary or secondary sialidase deficiency. Aberrant electrophoretic mobilities of many of the enzymes attributable to abnormal sialylation were found in all the patients. In ten of the patients seven of the enzymes were affected. The unaffected enzymes were beta-galactosidase, alkaline phosphatase and beta-glucuronidase. In the cells from the two patients with I cell disease (mucolipidosis II) in which sialidase is one of many deficient enzymes, beta-galactosidase, alpha-galactosidase, alpha-fucosidase and alpha-mannosidase were undetectable, alkaline phosphatase showed a normal electrophoretic mobility and acid phosphatase, adenosine deaminase, alpha-glucosidase and beta-D-N-acetylhexosaminidase showed aberrant mobilities.
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PMID:Electrophoretic analysis of glycoprotein enzymes in the sialidoses and mucolipidoses. 645 53

The enzyme properties of acid sialidase have been investigated in cultured fibroblasts. An extended period of homogenization at 0 degree C, did only minimally inactivate the enzyme and 90% and 80% of the activity was recovered after 3 and 5 minutes of homogenization respectively. Bovine serum albumin is an affective protector of the enzyme. The activity of the enzyme was 70% and 18% respectively at 23 degrees C and 0 degree C, in comparison with the activity measured at 37 degrees C. 55% of the sialidase activity was recovered after a homogenate had been kept frozen for 6 months at--20 degrees C. Methoxyphenyl-sialic acid, colominic acid, and sialyllactose are all competitive inhibitors. The Vmax value in fibroblasts of a patient with mucolipidosis II was about 40 times lower than in normal control fibroblasts.
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PMID:Methylumbelliferyl-N-acetyl-neuraminic acid (MU-NANA) sialidase in human fibroblasts. Further characterization of the enzyme. 716 16

A method to semiquantify urinary oligosaccharides from patients suffering from oligosaccharidurias is presented. 1-Phenyl-3-methyl-5-pyrazolone has been used to derivatize urinary oligosaccharides prior to analysis by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Disease-specific oligosaccharides were identified for several oligosaccharidurias, including GM1 gangliosidosis, GM2 gangliosidosis, sialic acid storage disease, sialidase/neuraminidase deficiency, galactosialidosis, I-cell disease, fucosidosis, Pompe and Gaucher diseases, and alpha-mannosidosis. The oligosaccharides were referenced against the internal standard, methyl lactose, to produce ratios for comparison with control samples. Elevations in specific urinary oligosaccharides were indicative of lysosomal disease and the defective catabolic enzyme. This method has been adapted to enable assay of large sample numbers and could readily be extended to other oligosaccharidurias and to monitor oligosaccharide levels in patients receiving treatment. It also has immediate potential for incorporation into a newborn screening program.
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PMID:Profiling oligosaccharidurias by electrospray tandem mass spectrometry: quantifying reducing oligosaccharides. 1611 43