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:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two positional isomers of sialyloligosaccharides were isolated from the urine of a patient with adult type sialidosis with partial deficiency of beta-galactosidase. From structural studies including sugar analysis, enzyme degradation and methylation analysis, the following structures are deduced; 1. alpha-AcNeu-(2 leads to 3)-beta-Gal-(1 leads to 4)-beta-GlcNAc-(1 leads to 2)-alpha-Man-(1 leads to 3)-beta-Man-(1 leads to 4)-GlcNAc 2. alpha-AcNeu-(2 leads to 3)-beta-Gal-(1 leads to 4)-beta-GlcNAc-(1 leads to 2)-alpha-Man-(1 leads to 6)-beta-Man-(1 leads to 4)-GlcNAc The sialyloligosaccharide 1 has previously been reported to be present in liver and urine of patients with mucolipidosis I, II and variant forms. The sialyloligosaccharide 2 was first demonstrated in human urine.
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PMID:Urinary sialyloligosaccharides in adult type sialidosis: occurrence of two positional isomers. 679 2

Neuraminidase deficiency has been demonstrated in cultured skin fibroblasts of patients who have adult type sialidosis with partial beta-galactosidase deficiency. A substantial amount of residual enzyme activity has been observed in leukocytes, however. To explain this discrepancy, the nature and distribution of the enzyme were studied. Neuraminidase activity was higher in lymphocytes than in granulocytes of normal controls. In patients' lymphocytes, neuraminidase activity was profoundly decreased and total sialic acid contents were increased 2.3-fold. Two neuraminidases, one sonication-labile and the other sonication-stable, were found in lymphocytes; the former was predominant in cultured skin fibroblasts. The defective enzyme in this disorder was found to be the sonication-labile neuraminidase in both cultured skin fibroblasts and lymphocytes.
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PMID:Neuraminidase deficiency and accumulation of sialic acid in lymphocytes in adult type sialidosis with partial beta-galactosidase deficiency. 680 93

Kinetic studies of 4-methylumbelliferyl neuraminidase activity were carried out in cultured skin fibroblasts from patients with various disorders of neuraminidase deficiency. Cell extracts from two patients with dysmorphic type sialidosis of infantile onset, with isolated deficiency of neuraminidase activity, and three patients with dysmorphic type sialidosis of juvenile onset, with combined deficiency of neuraminidase and beta-galactosidase activities, demonstrated 7-12 times higher apparent Km values than those of normal controls (1.0-1.5 mmol/l as compared with 0.12-0.15 mmol/l). The apparent Ki values for N-acetylneuraminic acid and colominic acid were also increased in the dysmorphic type (7-15 and 7-11 times the normal values, respectively). In contrast, in the normomorphic type, normal apparent Km and Ki values were found for 4-methylumbelliferyl neuraminidase activity in fibroblasts from one patient with isolated neuraminidase deficiency and two patients with combined deficiency of neuraminidase and beta-galactosidase. The altered kinetics in the dysmorphic cases indicates a primary defect in neuraminidase with a secondary deficiency of beta-galactosidase in patients with combined deficiency. It is not clear if the primary defect in the normomorphic cases involves a defect in neuraminidase other than a Km defect or if neuraminidase or both neuraminidase and beta-galactosidase deficiencies are secondary to another defect as yet undetermined.
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PMID:Km defect in neuraminidase of dysmorphic type sialidosis with and without beta-galactosidase deficiency. 681 Nov 61

We devised a sensitive method to assay for neuraminidase activities towards alpha-(2 leads to 3)-N-acetylneuraminosyl hexasaccharide and alpha-(2 leads to 6)-N-acetylneuraminosyl hexasaccharide, which were isolated from the urine of a patient with adult sialidosis with partial deficiency of beta-galactosidase. Standard assay conditions for the determination of these neuraminidase activities were established and the radiolabeled reduced derivatives of these substrates were used. The fibroblast neuraminidase had its maximum activity at pH 4.0-4.2, with Km values of 2.22 X 10(-3) and 4.17 X 10(-3) mol/l and Vmax values of 76.9 and 28.6 nmol . mg-1 protein . h-1 towards the 2 leads to 3 isomer and the 2 leads to 6 isomer, respectively. Neuraminidase deficiencies were found in the fibroblasts of adult sialidosis, mucolipidosis II and III. These studies were compared with the neuraminidase activity towards alpha-(2 leads to 3)-N-acetylneuraminosyl lactose.
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PMID:Radioassay method of neuraminidase towards N-acetylneuraminosyl hexasaccharides. 706 Feb 78

Human beta-galactosidase and alpha-neuraminidase deficient mucolipidosis [ML(gal-neur-)] is an inherited lysosomal enzymopathy which recently was designated as a sialidosis. We analyzed the neuraminidase deficiency of this disorder with genetic complementation analyses using a heterokaryon enrichment procedure. The genetic defects of two apparent variants of this disorder complemented the defects of the neuraminidase deficiency diseases, sialidosis I and mucolipidosis I, resulting in the restoration of neuraminidase activity in heterokaryons. The neuraminidase deficiency, therefore, may not be the primary defect in ML(gal-neur-) and is not an appropriate test for determining carrier status. The clinical and biochemical characteristics of this disorder suggest that a post-translational or processing event for these enzymes may be defective. The defect, however, is different from I-cell disease and pseudo-Hurler polydystrophy, two disorders of post-translational lysosomal enzyme biosynthesis, since complementation studies demonstrated recovery of intracellular beta-galactosidase and alpha-neuraminidase levels in heterokaryons. The lack of human beta-galactosidase expression in man-mouse somatic cell hybrids formed from fibroblasts of the infantile onset type disorder suggests that the defect is not corrected by the mouse genome. The ML(gal-neur-) disorder therefore appears to be a distinct subtype of the inherited neuraminidase deficiencies in which the defect mat occur in a post-translational or regulatory step which coordinately affects the expression of lysosomal beta-galactosidase and alpha-neuraminidase.
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PMID:Human beta-galactosidase and alpha-neuraminidase deficient mucolipidosis: genetic complementation analysis of the neuraminidase deficiency. 707 57

Defects of neuraminidase activities towards sialyloligosaccharides in fibroblasts and leucocytes and enhanced excretion of sialyloligosaccharides in urine were shown in patients with adult type sialidosis with partial deficiency of beta-galactosidase and cherry red spot-myoclonus syndrome. No differences in their neuraminidase residual levels and urinary excretion patterns on thin-layer chromatography were found between these two disorders. In mucolipidosis II and III patients, the neuraminidase activities towards sialyloligosaccharides were almost normal in leucocytes, although decreased in fibroblasts. The discrepancy of neuraminidase activities towards 2 leads to 3 and 2 leads to 6 sialyloligosaccharide isomers was not noticed in all cases.
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PMID:Neuraminidase activities in sialidosis and mucolipidosis. 709 97

The characteristics of the sialidase (N-acetyl-alpha-neuraminidase) of human leukocytes, fibroblasts and amniotic fluid cell cultures were determined with a radioactive assay method utilizing neuramin-[3H]lactitol as the enzyme substrate. Fibroblast cultures from patients with the inherited sialidase deficiency diseases including mucolipidosis I, sialidosis I and sialidosis II, juvenile type have less than 10% of normal sialidase activity using either this substrate, 2-(3'-methoxyphenyl)-N-acetyl-alpha-neuraminic acid, or 2'-(4-methylumbelliferyl)-N-acetyl-alpha-neuraminic acid. The total sialic acid content of fibroblasts and leukocytes from mucolipidosis I and sialidosis I patients is greatly elevated; this parameter is useful in establishing a diagnosis of sialidase deficiency. The sialic acid content of sialidosis II, juvenile type, with coexistent sialidase and beta-galactosidase deficiencies, is only slightly elevated above normal levels. A patient with mucolipidosis I has 16% of normal neuramin-[3H]lactitol sialidase activity in his peripheral leukocytes. His parents were clearly distinguished from the normal range using leukocyte enzyme levels and a maternal aunt was identified as a possible carrier. The presence of this enzyme in amniotic fluid cell cultures, both fibroblastic and mixed cell type, makes possible the prenatal detection of these diseases. A pregnancy from a family at risk for having a child with mucolipidosis I was monitored by amniocentesis and subsequent sialidase measurement of the amniotic fluid cell cultures.
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PMID:Mucolipidosis I: studies of sialidase activity and a prenatal diagnosis. 722 21

Isolated deficiency of the lysosomal hydrolase acid neuraminidase results in multisystem storage of sialic acid-rich oligosaccharides. Wide phenotypic diversity occurs within this biochemical defect. We studied three cases of an infantile form of mucolipidosis I in which the phenotype is dominated by severe Hurloid features. These patients excreted excessive amounts of sialic acid-rich oligosaccharides in their urine, and storage of similar compounds was shown in tissues and cultured fibroblasts. Cultured fibroblasts demonstrated an isolated deficiency of acid neuraminidase; beta-galactosidase levels were normal.
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PMID:Mucolipidosis I (acid neuraminidase deficiency). Three cases and delineation of the variability of the phenotype. 727 May 11

Four positional isomers of sialyloligosaccharides were isolated from the urine of an adult patient with sialidosis with partial deficiency of beta-galactosidase. From structural studies including compositional sugar analysis, exoglycosidase digestion, chemical ionization mass spectrometry, proton nuclear magnetic resonance spectrometry, and methylation analysis, their structures were deduced to be as follows: 1. AcNeu alpha 2 leads to 3 Gal beta 1 leads to 4GlcNac beta 1 leads to 2Man alpha 1 leads to 3Man beta 1 leads to 4GlcNac 2. AcNeu alpha 2 leads to 3Gal beta 1 leads to 4GlcNac beta 1 leads to 2Man alpha 1 leads to 6Man beta 1 leads to 4GlcNac 3. AcNeu alpha 2 leads to 6Gal beta 1 leads to 4GlcNac beta 1 leads to 2Man alpha 1 leads to 3Man beta 1 leads to 4GlcNac 4. AcNeu alpha 2 leads to 6Gal beta 1 leads to 4GlcNac beta 1 leads to 2Man alpha 1 leads to 6Man beta 1 leads to 4GlcNac Sialyloligosaccharides 1 and 3 have previously been found in the liver and urine of patients with mucolipidosis I, II, and variable forms, but sialyloligosaccharides 2 and 4 have not previously be found in human urine.
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PMID:Four positional isomers of sialyloligosaccharides isolated from the urine of a patient with sialidosis. 729 59

We describe the partial characterization and some properties of fibroblast and leucocyte neuraminidase towards 2 leads to 3 and 2 leads to 6 sialyllacose, and 2 leads to 3 and 2 leads to 6 sialylhexasaccharide which were isolated from the urine of a patient with adult sialidosis with partial beta-galactosidase deficiency. Neuraminidase activities were assayed using the radioactive-labeled derivatives of these saccharide substrates. These neuraminidases (acylneuraminyl hydrolase, EC 3.2.1.18) were partially inactivated by homogenization, sonication and freeze-thawing treatment. The leucocyte neuraminidase was more labile than that of fibroblasts. Fibroblast neuraminidase had about a 10-fold higher activity than leucocyte neuraminidase towards the respective substrates. The neuraminidase from fibroblasts and leucocytes were each able to hydrolyze 2 leads to 3 isomers 2-3 times faster than 2 leads to 6 isomers and the sialyllactoses 1.5-3.0-times faster than sialylhexasaccharides. Neuraminidase activities towards all four substrates were deficient in fibroblasts and leucocytes from the patients with adult sialidosis. Loss of activity was especially prominent in fibroblasts, while considerable residual activities (about 20-30%) remaining in leucocytes. In mucolipidosis II and III patients, these neuraminidase activities showed normal levels in leucocytes, although they were decreased in fibroblasts. The discrepancy between neuraminidase activities towards 2 leads to 3 and 2 leads to 6 isomers was not found in all the cases.
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PMID:Partial characterization and studies of fibroblast and leucocyte neuraminidase activities towards sialyloligosaccharides in adult sialidosis and mucolipidosis II and III. 731 38


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