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 children presenting with a mild form of Morquio's syndrome are reported. Clinically, there was a characteristic brevity of the trunk and slit lamp examination showed discrete corneal opacities. On X-ray films, generalized plastyspondylia was moderate but it was associated with hypoplasia of the odontoid process. Acetabula were enlarged with coxa valga; obliquity of inferior radio-cubital extremity was associated with a sharp pattern of the proximal end of metacarpi. Epiphyseal cartilage chondrocytes also looked like those of Morquio's syndrome: large cells containing numerous vacuoles, limited by a single smooth membrane. On the other hand, no keratosulfate was found in urines and N-acetylgalactosamine-6-sulfate-sulfatase and beta-galactosidase assays in fibroblasts were normal. Thus, this mild form is different from the so-called Morquio's syndromes types A and B.
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PMID:[Heterogeneity of formes frustes of Morquio's disease]. 621 49

The receptor site for transferrin in normal human erythroid precursor cells was studied by fluorescence microscopy. F-transferrin saturated with iron was used as probe of the available receptor sites on reticulocytes and nucleated red cells. In a series of experiments specificity and certain structural details of the ligand site were evaluated. Hydrolytic cleavage of exposed carbohydrate moieties by purified glycosidases revealed increased fluorescence after treatment of fixed cells by neuramindase, no perceptible change after N-acetylhexosaminidase treatment, but a pronounced decrease after exposure to beta-galactosidase. Inhibitor studies with monosaccharides and tryptic glycopeptides of normal reticulocytes complemented and amplified the results obtained with enzymes. The data suggest that an oligosaccharide chain is essential for specific transferrin binding to erythroid precursors. N-acetyl-neuraminic acid, galactose, N-acetylgalactosamine, and fucose appear to be saccharides on the receptor. These studies also demonstrate the applicability of fluorescence microscopic methods to qualitative structural analysis of receptor biochemistry.
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PMID:Fluorescence microphotometric studies of the transferrin receptor in human erythroid precursor cells. 625 79

Rat glioma X mouse neuroblastoma hybrid neurotumor cells (NG108-15), synchronized by amino acid deprivation, showed a cell-cycle-dependent peak of activity of a ganglioside N-acetylgalactosaminyl transferase 14-24 h following release from the cell cycle block (S/G2 phase). Maximal expression of two typical lysosomal hydrolases, N-acetyl-beta-hexosaminidase and beta-galactosidase, occurred between 18 and 21 h following release (S phase), declining to G1 phase levels during the peak of N-acetylgalactosamine (GalNAc) transferase activity. In addition, glycosyltransferase activity in G2 phase cells showed an increase in apparent Vmax (suggesting the presence of more enzyme/mg of cell protein) and apparent binding affinity for uridine diphosphate N-acetylgalactosamine (UDP-GalNAc) (32 versus 14 microM) when compared to transferase activity in the G1 phase. However, the opioid peptide enkephalin [D-Ala2, D-Leu5], which inhibits ganglioside GalNAc transferase activity in unsynchronized NG108-15 cultures, was much more inhibitory in whole cells 8 h after release from the cell cycle block (G1 phase) than in cells 20 h after release (G2 phase), with 50% inhibition occurring at 2 X 10(-9) M and 2 X 10(-7) M, respectively. These results suggest that the GalNAc transferase activity is regulated in more than one way during the cell cycle, since both Vmax and Km changes are observed, and that the cyclic AMP-dependent mechanism by which opiates reduce transferase activity is receptor mediated and cell cycle dependent.
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PMID:Cell-cycle dependence of a ganglioside glycosyltransferase activity and its inhibition by enkephalin in a neurotumor cell line. 642

This report describes a third mucopolysaccharidosis in animals: canine mucopolysaccharidosis VII. The affected dog was the offspring of a father-daughter mating. Weakness in the rear legs was evident at 8 weeks of age and became progressively worse. He had a large head, a shortened maxilla, and corneal granularities. Most joints were extremely lax, easily subluxated, with joint capsules that were swollen and fluctuant. The dog was alert and had apparently normal pain perception. At 13 months of age, there was radiographic evidence of extensive skeletal disease including bilateral femoral head luxation, abnormalities in the shape and density of the carpal and tarsal bones, radiolucent lesions of the epiphyseal regions of most long bones, and cervical vertebral dysplasia and platyspondylia. The electrophoretic pattern of precipitated glycosaminoglycans indicated a predominance of chondroitin sulfate. The animal died suddenly from gastric dilatation. There was generalized hepatomegaly, thickening of the atrioventricular heart valves, and generalized polyarthropathy. Vacuolated cytoplasm was observed in hepatocytes, keratocytes, fibroblasts, chondrocytes and cells of the synovial membrane, retinal pigment epithelium, and cardiac valves. Neurons had cytoplasmic vacuoles. Electron microscopy demonstrated membrane-bound cytoplasmic inclusions in polymorphonuclear leukocytes, hepatocytes, synovium, heart valves and spleen. The activities of 12 lysosomal hydrolases were determined in liver from the affected and control dogs: beta-glucuronidase (EC 3.2.1.31), beta-hexosaminidases A and B (EC 3.2.1.30), alpha-hexosaminidase (EC 3.2.1.-), alpha-L-iduronidase (EC 3.2.1.76), alpha-galactosidase A (EC 3.2.1.22), beta-galactosidase (EC 3.2.1.23), arylsulfatases A and B (EC 3.1.6.1), acid alpha-mannosidase (EC 3.2.1.24), acid beta-mannosidase (EC 3.2.1.25), and N-acetyl-D-galactosamine-6-sulfate sulfatase (EC 3.1.6.-).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Beta-glucuronidase deficiency in a dog: a model of human mucopolysaccharidosis VII. 643 80

A quantitative cytochemical method for the measurement of beta-galactosidase activity in cultured human skin fibroblasts has been developed using 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside as the indigogenic substrate. The method relies upon the oxidation of the primary reaction product by ferro/ferricyanide during which an insoluble indigo dye is generated as the final reaction product. The reaction was linear with time up to 60 min using the final cytochemical standard procedure. The enzyme showed maximum activity at pH 4.0 to 4.1. The concentration optima of indigogenic substrate and potassium ferro/ferricyanide were 3.67 mM and 3.13 mM respectively. The presence of sodium chloride activated beta-galactosidase up to 100 mM, but was inhibitory above that concentration. The enzyme was inhibited by N-ethylmaleimide, N-acetyl-D-galactosamine and heparin. The enzyme molecules were shown to diffuse out of the cells using media without a suitable inert colloid stabilizer. However, diffusion was completely prevented by using polyvinyl alcohol (PVA) grade G18/140. Air-drying of cells was essential to make the cell membrane permeabel to the substrate and, thereby, to avoid a pronounced lag phase. However, in a biochemical analysis, air-drying itself caused a decrease in enzyme activity to 43% of the control. Even after air-drying lysosomal latency could still be demonstrated by using PVA grade G04/140. Control persons, one carrier of and two patients with beta-galactosidase deficiency were easily identified as belonging to three separate groups by using the cytochemical assay. It is proposed that the quantitative cytochemical approach may also be applied to cultured human amniotic fluid cells or chorion biopsies giving a rapid prenatal diagnosis of beta-galactosidase deficiency due to the small number of cells needed in the analysis.
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PMID:A quantitative cytochemical assay of beta-galactosidase in single cultured human skin fibroblasts. 643 94

Three major glycoproteins of calf thyroid plasma membranes were preferentially solubilized by chloroform/methanol extraction and recovered along with glycolipids in the aqueous phase. After removal of lipid from this extract, a fraction was obtained which accounted for about 20% of the carbohydrate of the membrane but only 2% of its peptide weight. Partial resolution of the components could be achieved by filtration on Bio-Gel A-5m, while preparative polyacrylamide gel electrophoresis resulted in the isolation in homogeneous form of approximately equal amounts of the three glycoproteins which were designated as GP-1, GP-2, and GP-3, in order of their increasing mobility. These purified glycoproteins appeared on electrophoresis as single components by periodic acid-Schiff staining as well as by distribution of radioactivity following 3H or 14C labeling. Molecular weights of 100,000, 59,000, and 20,000 were estimated for the three components on the basis of their retardation coefficients. The total carbohydrate content by weight determined for GP-1, GP-2, and GP-3 was 56, 57, and 79%, respectively. The sugar constituents were mannose, galactose, fucose, glucosamine, galactosamine, and sialic acid, which were present in the following mol per cents: GP-1, 13:32:5:24:13:12; GP-2, 20:28:3:32:5:11; GP-3, 12:36:2:34:6:10. Studies performed with various lectins (Bandeiraea simplicifolia I and I (B4), wheat germ, Ricinus communis, and soybean) on the gycoproteins, either native or after treatment with glycosidases (alpha- or beta-galactosidase, neuraminidase), indicated that sialic acid and alpha-linked galactose were in terminal positions, beta-galactosyl residues were internally located, and chains containing the sequence sialic acid-N-acetylgalactosamine were present.
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PMID:Isolation and characterization of three major glycoproteins from thyroid plasma membranes. 677 52

Simultaneous or sequential treatment of rat adipocytes with neuraminidase plus beta-galactosidase decreased insulin binding by 43%. No modification was observed with either enzyme individually. alpha-Mannosidase enhanced insulin binding (38%), whereas beta-N-acetylglucosaminidase and alpha-L-fucosidase were ineffective. Lectins that interact with galactose (Ricinus communis I, RCAI), mannose, Lens culinaris agglutinin (LCA), Concanavalin A (Con A) or N-acetylglucosamine (wheat-germ agglutinin, WGA) decreased insulin binding by 43, 57, 59 and 85% respectively. Lectin inhibition was dose-dependent, saturable and prevented by specific monosaccharides. RCAI, LCA, Con A and WGA decreased the insulin dissociation process by 45, 90, 78 and 84% respectively. Lectins specific for sialic acid, terminal galactose, N-acetylgalactosamine or fucose (Limulus polyphemus, peanut, soybean and Ulex I agglutinins) did not modify either insulin binding or dissociation. These results indicate involvement of penultimate D-galactose, internal N-acetyl-D-glucosamine and D-mannose residues in both processes. They suggest that, in rat adipocytes, a glycosidic moiety participates in the insulin-receptor interaction through N-linked oligosaccharides of the 'complex type'.
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PMID:Further characterization of the insulin receptor glycosidic moiety in rat adipocytes. 679 21

We have characterized the UDP-galactose: alpha-N-acetylgalactosaminide beta 3 galactosyltransferase in human tracheal epithelium using asialo ovine submaxillary mucin as the acceptor. Maximal enzyme activity was obtained at pH 6.0-7.5 and at 20-25 mM MnCl2 and at 2% Triton X-100. Cd2+ could substitute for Mn2+ as the divalent ion cofactor. Spermine, spermidine, putrecine, cadaverine, and poly-L-lysine stimulated the enzyme activity at low (2.5 mM) MnCl2 concentration. The apparent Michaelis constants for N-acetylgalactosamine, asialo ovine submaxillary mucin, and UDP-galactose were 15.5, 1.14, and 1.36 mM, respectively. The enzyme activity was not affected by alpha-lactalbumin. The alpha-N-acetygalactosaminide beta 3 galactosyltransferase was shown to be different from the N-acetylglucosamine galactosyltransferase by acceptor competition studies. The product of galactosyltransferase was identified as Gal beta 1 leads to 3GalNAc alpha Ser (Thr) by (a) isolation of [14C]Gal-GalNAc-H2 after alkaline borohydride treatment of the 14C-labeled product, (b) establishment of the beta-configuration of the newly synthesized glycosidic bond by its complete cleavage by bovine testicular beta-galactosidase, and (c) assignment of the 1 leads to 3 linkage by identification of threosaminitol obtained from the oxidation of the disaccharide with periodic acid followed by reduction with sodium borohydride, hydrolysis in 4 N HCl, and analysis on an amino acid analyzer. The 1 leads to 3 linkage was confirmed by its resistance to jack bean beta-galactosidase and by the presence of a m/e 307 ion fragment and the absence of a m/e 276 ion by gas-liquid chromatography-mass spectrometry analysis. When acid and beta-galactosidase-treated human tracheobronchial mucin was used as the acceptor, 3.3% of the product was found as [14C]Gal-GalNAc-H2. The remainder of the [14C]Gal was found in longer oligosaccharides formed by a different beta-galactosyltransferase. This galactosyltransferase is slightly inhibited by alpha-lactalbumin and stimulated by spermine.
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PMID:Mucin biosynthesis. Characterization of UDP-galactose: alpha-N-acetylgalactosaminide beta 3 galactosyltransferase from human tracheal epithelium. 680 62

Neutral glycosphingolipids were isolated from the malignant cells of several patients with different types of acute leukemia. Analyses were performed by high performance liquid chromatography combined with enzymatic hydrolysis of glycosphingolipids using glycosidases (Escherichia freundii endo-beta-galactosidase, jack bean beta-galactosidase, and beef kidney beta-hexosaminidase). We found that acute leukemia cells contain very little or none of the more complex neutral glycosphingolipids that are found in normal leukocytes or chronic leukemia cells. Lymphoblasts, in particular, are rich in neutral glycosphingolipids with only 1 or 2 carbohydrate units. The most significant finding of our study was that, in contrast to normal leukocytes and chronic leukemia cells which have a single predominant tetraosylceramide species, acute leukemia cells (9 out of 10 patients analyzed) were found to have significant amounts of both globo (GalNAc beta 1 leads to 3Gal alpha 1 leads to 4Gal beta 1 leads to 4Glc beta 1 leads to 1ceramide) and neolactotetraosylceramide (Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc beta 1 leads to 1ceramide). These results indicate that the composition of neutral glycosphingolipids in acute leukemia cells differs significantly from that found in normal or chronic leukemia cells.
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PMID:Neutral glycosphingolipids of human acute leukemias. 695 4

Band-3 glycoprotein was purified from human blood-group-A erythrocyte membranes by selective solubilization and gel chromatography on Sepharose 6B in the presence of sodium dodecyl sulphate. The purified glycoprotein was subjected to hydrazinolysis in order to release the carbohydrate moiety. The released oligosaccharides were N-acetylated and applied to a column of DEAE-cellulose. Most of the band-3 oligosaccharides obtained were found to be free of sialic acids. When this neutral fraction was subjected to gel chromatography on a column of Sephadex G-50, two broad peaks were observed indicating that the band-3 glycoprotein was heterogeneous in the size of the oligosaccharide moieties. All fractions from gel chromatography were found to contain galactose, mannose, N-acetylglucosamine and fucose. The higher-molecular-weight (mol.wt. 3000-8000) peak consisted of fucose, mannose, galactose, N-acetylglucosamine and N-acetylgalactosamine in a molar proportion of 1.6:3.0:8.4:10.5:0.2. Most of these oligosaccharides were digested with a mixture of beta-galactosidase and beta-N-acetylhexosaminidase after alpha-L-fucosidase treatment to give a small oligosaccharide with the structure alpha Man2-beta Man-beta GlcNAc-GlcNAc. Methylation studies and limited degradation by nitrous acid deamination showed that the oligosaccharides contained the repeating disaccharide Gal beta 1----4GlcNAc beta 1----3, with branching points at C-6 of some of the galactose residues. These results indicate that a major portion of the band-3 oligosaccharide has a common core structure, with heterogeneity in the numbers of the repeating disaccharides, and contains fucose residues both in the peripheral portion and in the core portion. Haemagglutination tests were also carried out to determine the blood-group specificities of the glycoprotein and the results demonstrated the presence of both blood-group-H and I antigenic activities.
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PMID:The carbohydrate moiety of band-3 glycoprotein of human erythrocyte membranes. 718 22


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