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)

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

We analyzed the subcellular localization of sialidases in human lymphocytes from a patient with adult type sialidosis with partial beta-galactosidase deficiency and normal controls. Sialidase activities were measured with alpha,2 leads to 3 NeuAc-lactitol, 4-methylumbelliferyl-NeuAc and GM3 ganglioside as substrates. Sialidases in the lysosomes were sonication-labile and hydrolyzed mainly hydrophilic substrates such as NeuAc-lactitol and 4-methylumbelliferyl-NeuAc, but hydrolyzed subsidiarily GM3 ganglioside. On the other hand, sialidases in the plasma membrane were sonication-stable and hydrolyzed both hydrophilic substrates and GM3 ganglioside. In sialidosis with partial beta-galactosidase deficiency, the sialidases of the lysosomes showed 3-5% activity toward hydrophilic substrates and 25% activity toward GM3 ganglioside as compared with sialidase activities of the controls. However, there are no differences in the activities of the sialidases in the plasma membrane. These results demonstrate that the essential defect in this disease is the deficiency of a lysosomal sialidase.
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PMID:Lysosomal sialidase deficiency in sialidosis with partial beta-galactosidase deficiency. 640 33

Two sisters and one brother, all with normal intelligence and no evidence of neurological abnormality, present progressive spondyloepiphyseal dysplasia, stunted growth, corneal opacities, and increased keratansulfaturia. Cultured skin fibroblasts from one of the children showed a remarkable deficiency of acid beta-galactosidase in association with normal activities of N-acetylgalactosamine-6-sulfate sulfatase and sialidase. Acid beta-galactosidase was also deficient in leukocytes of two children. Leukocytes of the parents exhibited intermediate activities, which suggests the primary nature of beta-galactosidase deficiency. Patients with MPS IV-B may be severely affected.
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PMID:Morquio-B disease, spondyloepiphyseal dysplasia associated with acid beta-galactosidase deficiency. Report of three cases in one family. 640 99

Cultured skin fibroblasts from patients with the lysosomal storage disease galactosialidosis lack a 54-kDa protein which is a precursor of 32-kDa and 20-kDa proteins, which immunoprecipitate with human anti-beta-galactosidase antiserum. The lack of a 32-kDa "protective protein" results in a combined deficiency of beta-galactosidase and sialidase. The mechanism of protection of lysosomal beta-galactosidase against proteolytic degradation is elucidated by sucrose density gradient centrifugation and immunoprecipitation studies. In normal fibroblasts at the low intralysosomal pH, more than 85% of beta-galactosidase exists as a high molecular weight (600-700 kDa) multimer and about 10% as a monomer of 64-kDa. In mutant cells from galactosialidosis patients, the residual enzyme activity, about 10%, is present as a monomer and no multimer exists. After addition of the 54-kDa precursor form of the protective protein, the density pattern of beta-galactosidase in galactosialidosis cells is normalized. Immunoprecipitation studies after sucrose density gradient centrifugation on homogenate and on purified beta-galactosidase from normal fibroblasts show that the protective protein is associated only with the multimeric form of beta-galactosidase. We propose that intralysosomal protection against proteolysis of beta-galactosidase and sialidase is accomplished by aggregation into a high molecular weight complex consisting of multimeric beta-galactosidase, sialidase, and protective protein. The genetic deficiency of the latter, as in galactosialidosis, results in a rapid degradation of monomeric beta-galactosidase and a loss of sialidase activity.
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PMID:The relation between human lysosomal beta-galactosidase and its protective protein. 641 49

Previous studies using the lectin RCA-I from Ricinus communis have indicated that several lysosomal enzymes in the fibroblasts of patients deficient in beta-galactosidase carry excess terminal galactose. Electrophoretic studies have shown that the same enzymes and the non-lysosomal adenosine deaminase also show excess terminal sialic acid in patients deficient in sialidase. In this paper we confirm, using Jack-bean beta-galactosidase, that the binding to RCA-I of the purified N-acetyl-beta-D-hexosaminidase from a patient with GM1 gangliosidosis depends on a terminal beta-linked galactose. We provide evidence, using bacterial sialidase and measuring the binding to RCA-I, for excess subterminal galactose on the enzymes of patients deficient in sialidase. We also show that adenosine deaminase from the fibroblasts of patients deficient in beta-galactosidase has increased binding to RCA-I. These observations suggest that in healthy individuals the carbohydrate structure of the precursors of lysosomal enzymes and possibly some other glycoproteins also includes extended carbohydrate side chains with terminal sialic acid and subterminal galactose, and that the mature enzyme extracted from tissues is the product of degradation.
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PMID:The role of lysosomal sialidase and beta-galactosidase in processing the complex carbohydrate chains on lysosomal enzymes and possibly other glycoproteins. 643 95

A patient with combined deficiency of sialidase and beta-galactosidase is described. This now 39-year-old man, who is of Japanese origin, showed gradually progressive clinical features from the age of six years. Many of these features are commonly found in sialidosis type 2 or in GM1-gangliosidosis. Both sialidase and beta-galactosidase activities were deficient in leucocytes and cultured fibroblasts. Leucocytes of his mother showed activities of both enzymes in the lower limit of the control range. Morphologically, the pattern of storage products in a skin biopsy resembled in many respects that seen in GM1-gangliosidosis. Moreover, storage products which could be typical of sialidosis were also observed. Since the patient showed angiokeratomata, the morphological findings were compared with those specific to Fabry's disease, but no similarities were found. An enzymological diagnosis of the disease is most reliable on cultured fibroblasts, discriminating it from sialidosis type 2 and GM1-gangliosidosis. In view of recent findings, leucocytes seem to be less suitable for the establishment of the diagnosis galactosialidosis.
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PMID:Combined sialidase (neuraminidase) and beta-galactosidase deficiency. Clinical, morphological and enzymological observations in a patient. 643 81

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

A new procedure for a sialidase assay, by bioluminescence, has been developed. The substrate, N- acetylneuraminyllactose (sialyllactose), hydrolysed by the sialidase activity, releases lactose. This lactose is hydrolysed with beta-galactosidase. The released galactose is oxidized with galactose dehydrogenase and NAD. The NADH produced in the last step is measured by a luminescence system, coupling two enzymes, NAD(P)H dehydrogenase (FMN) and luciferase. This microassay, which is specific, rapid, simple and ultra-sensitive, is a measure for amounts as little as (at least) 5 pmol of N-acetylneuraminic acid (corresponding to 0.15 ng of the released sialic acid). It uses commercialized reagents (non-radioisotopic) and avoids interferences common in other procedures. This method has been used for measuring sialidase activity directly on intact virus, avoiding inconvenient modifications produced in the extraction of the enzyme. The specific activity of sialidase of influenza virus X31 (H3N2), determined by this procedure, is 0.65 U/mg of total virus protein.
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PMID:Sialidase assay by luminescence in the low picomole-range of sialic acid. Its application to the measurement of this activity in influenza virus. 673 52

Two young adult siblings were diagnosed as having a deficiency of acid beta-galactosidase activity in leukocytes and fibroblasts. The parents had enzyme levels approximately half of the normal level, consistent with this being the primary enzymatic lesion. Sialidose activities measured with natural and synthetic substrates in the patient's skin fibroblast cultures were normal. Hybridization of one of these patient's cells with cells from a patient with GM1 gangliosidosis, Type 1 did not show complementation of beta-galactosidase activity. However, when the cells from the patient were hybridized with cells from a patient with combined sialidase and beta-galactosidase deficiency, complementation was observed. These two siblings have ataxia, mild intellectual deterioration, slurred speech, mild vertebral changes and little, if any, visceromegaly. They do not have myoclonus, seizures or cherry-red spots, which are found in most patients with combined sialidase and beta-galactosidase deficiency. These patients are discussed with regard to other patients in the literature called variant or adult GM1 gangliosidosis.
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PMID:Adult GM1 gangliosidosis: clinical and biochemical studies on two patients and comparison to other patients called variant or adult GM1 gangliosidosis. 677 95

The extent and the specificity of the initial cell attachment induced by various proteins coated on plastic surfaces have been studied with the following results: (a) Cell adhesion on the surfaces coated with sialidase and beta-galactosidase was as strong as on concanavalin A and limulus lectin-coated surfaces and the reactions were strongly inhibited by glycosidase inhibitors or by competitive substrates. The adhesion on sialidase was inhibited by 2-deoxy-2,3-dehydro-N-acetylneuraminic acid and by polysialoganglioside (GT1b) at low concentration (0.05-0.1 mM). The cell adhesion on beta-galactosidase coat was inhibited by 1,4-D-galactonolactone and beta-methylgalactoside but not by alpha-methylgalactoside. Thus, the initiation of cell adhesion on glycosidase surfaces could be mediated through the interactions of the specific binding sites of the enzyme surface with the cell surface substrates under physiological conditions. (b) Cell adhesion on various lectins could be blocked by various competing monosaccharides at the concentrations similar to the inhibitory concentrations for binding of lectins from solution to the cells. (c) Cell adhesion on fibronectin surfaces as well as on gelatin-coated surfaces was equally inhibited by GT1b at relatively high concentrations (0.25-0.5 mM). Lower concentrations of GT1b (0.05-0.1 mM) inhibited the cell adhesion on surfaces of Limulus lectin and sialidase. It is suggested that the cell adhesion mediated by fibronectin is based on yet unknown interactions in contrast to a specific cell adhesion through glycosidases and lectins.
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PMID:Studies on cell adhesion and recognition. I. Extent and specificity of cell adhesion triggered by carbohydrate-reactive proteins (glycosidases and lectins) and by fibronectin. 678 7


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