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)

Incubation of human vitamin D3-binding protein (Gc protein), with a mixture of immobilized beta-galactosidase and sialidase, efficiently generated a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase, and isolation of the intermediates with immobilized lectins, revealed that either sequence of hydrolysis of Gc glycoprotein by these glycosidases yields the macrophage-activating factor, implying that Gc protein carries a trisaccharide composed of N-acetylgalactosamine and dibranched galactose and sialic acid termini. A 3 hr incubation of mouse peritoneal macrophages with picomolar amounts of the enzymatically generated macrophage-activating factor (GcMAF) resulted in a greatly enhanced phagocytic activity. Administration of a minute amount (10-50 pg/mouse) of GcMAF resulted in a seven- to nine-fold enhanced phagocytic activity of macrophages. Injection of sheep red blood cells (SRBC) along with GcMAF into mice produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days.
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PMID:Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production. 907 Jun 63

A serum glycoprotein, Gc protein (vitamin D3-binding protein), can be converted by beta-galactosidase of B cells and sialidase of T cells to a potent macrophage-activating factor (MAF), a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is the precursor for MAF. Treatment of Gc protein with immobilized beta-galactosidase and sialidase generates a remarkably high titered macrophage-activating factor (GcMAF). When peripheral blood monocytes/ macrophages (designated macrophages) of 33 systemic lupus erythematosus patients were incubated with GcMAF (100 pg/ml), the macrophages of all patients were activated as determined by superoxide generation. However, the precursor activity of patient plasma Gc protein was lost or reduced in these patients. Loss of the precursor activity was the result of deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase activity found in the patient plasma. Levels of plasma alpha-N-acetylgalactosaminidase activity in individual patients had an inverse correlation with the MAF precursor activity of their plasma Gc protein. Deglycosylated Gc protein cannot be converted to macro-phage-activating factor. The resulting defect in macro-phage activation may lead to an inability to clear pathogenic immune complexes. Thus, elevated plasma alpha-N-acetylgalactosaminidase activity resulting in the loss of MAF precursor activity and reduced macro-phage activity may play a role in the pathogenesis of systemic lupus erythematosus.
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PMID:Deglycosylation of serum vitamin D3-binding protein by alpha-N-acetylgalactosaminidase detected in the plasma of patients with systemic lupus erythematosus. 907 53

Helicobacter pylori adhere to Kato III and Hela S3 cells in monolayer cultures. To explore whether cell surface glycoconjugates on these two cell lines mediate binding of H. pylori, various carbohydrates, glycoproteins, and glycolipids were tested to inhibit H.pylori cell adhesion. The adhesion was measured (i) with a urease-based assay and (ii) by cells stained with fluorescein. Sodium periodate and sialidase treatment (but not alpha- or beta-galactosidase, heparitinase,lysozyme, or trypsin) inhibited H. pylori binding to both cell lines. Sulfatides and sulfated glycoconjugates (50 microg/ml) but not heparin or a number of simple carbohydrates inhibited binding (1 mg/ml). The two H.pylori strains studied (CCUG 17874 and strain 25) showed high binding of soluble 125I-labeled heparin and other sulfated carbohydrate compounds.
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PMID:Sulfatides inhibit binding of Helicobacter pylori to the gastric cancer Kato III cell line. 909 25

Vitamin D3-binding protein (DBP; human DBP is known as Gc protein) is the precursor of macrophage activating factor (MAF). Treatment of mouse DBP with immobilized beta-galactosidase or treatment of human Gc protein with immobilized beta-galactosidase and sialidase generated a remarkably potent MAF, termed DBPMAF or GcMAF, respectively. The domain of Gc protein responsible for macrophage activation was cloned and enzymatically converted to the cloned MAF, designated CdMAF. In Ehrlich ascites tumor-bearing mice, tumor-specific serum alpha-N-acetylgalactosaminidase (NaGalase) activity increased linearly with time as the transplanted tumor cells grew in the peritoneal cavity. Therapeutic effects of DBPMAF, GcMAF, and CdMAF on mice bearing Ehrlich ascites tumor were assessed by survival time, the total tumor cell count in the peritoneal cavity, and serum NaGalase activity. Mice that received a single administration of DBPMAF or GcMAF (100 pg/mouse) on the same day after transplantation of tumor (1 x 10(5) cells) showed a mean survival time of 35 +/- 4 days, whereas tumor-bearing controls had a mean survival time of 16 +/- 2 days. When mice received the second DBPMAF or GcMAF administration at day 4, they survived more than 50 days. Mice that received two DBPMAF administrations, at days 4 and 8 after transplantation of 1 x 10(5) tumor cells, survived up to 32 +/- 4 days. At day 4 posttransplantation, the total tumor cell count in the peritoneal cavity was approximately 5 x 10(5) cells. Mice that received two DBPMAF administrations, at days 0 and 4 after transplantation of 5 x 10(5) tumor cells, also survived up to 32 +/- 4 days, while control mice that received the 5 x 10(5) ascites tumor cells only survived for 14 +/- 2 days. Four DBPMAF, GcMAF, or CdMAF administrations to mice transplanted with 5 x 10(5) Ehrlich ascites tumor cells with 4-day intervals showed an extended survival of at least 90 days and an insignificantly low serum NaGalase level between days 30 and 90.
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PMID:Immunotherapy of BALB/c mice bearing Ehrlich ascites tumor with vitamin D-binding protein-derived macrophage activating factor. 918 19

Procyclic forms of Trypanosoma brucei have been genetically modified to express the major metacyclic variant surface glycoprotein (VSG variant AnTat 11.17) of Trypanosoma gambiense. The VSG is expressed in an intact membrane-bound form that can be detected over the entire plasma membrane, together with procyclin, and as a series of lower-molecular-mass fragments that are mostly soluble degradation products. The presence of degraded VSG in the cells and the culture medium suggests that VSG is not efficiently processed and/or efficiently folded when expressed in procyclic cells. The level of procyclin expressed on the surface of these cells is slightly reduced, although there is no difference in procyclin mRNA levels. The intact membrane-bound form of the VSG is N-glycosylated with oligomannose structures and contains a glycosylphosphatidylinositol (GPI) membrane anchor that can be biosynthetically labelled with [3H]ethanolamine. The anchor is sensitive to mammalian GPI-specific phospholipase D but, like the anchor of procyclin, it is resistant to the action of bacterial phosphatidylinositol-specific phospholipase C. This pattern of phospholipase sensitivity suggests that the GPI anchor acquired by VSG when expressed in procyclics is acylated on the inositol ring and therefore resembles a procyclic procyclin-type anchor rather than a trypomastigote VSG-type anchor with respect to the lipid structure. The VSG expressed in procyclics was sensitive to the action of a mixture of sialidase, beta-galactosidase and beta-hexosaminidase, suggesting that the VSG GPI anchor also contains a sialylated polylactosamine side-chain modification similar to that described for procyclin. These results indicate that the nature of the protein expressed has little influence on the post-translational modifications performed in the secretory pathway of procyclic trypanosomes.
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PMID:Expression of a variant surface glycoprotein of Trypanosoma gambiense in procyclic forms of Trypanosoma brucei shows that the cell type dictates the nature of the glycosylphosphatidylinositol membrane anchor attached to the glycoprotein. 921 Apr 13

Beta-D-Xylopyranosides, such as p-nitrophenyl-beta-D-xylopyranoside (Xyl-Np) or 4-methylumbelliferyl-beta-D-xylopyranoside (Xyl-MeUmb), when added to the culture medium of human skin fibroblasts have previously been shown to produce some Np- or MeUmb-oligosaccharides related to the regulation of glycosaminoglycan biosynthesis. Among these oligosaccharide derivatives, we synthesized the trisaccharide derivative NeuAc(alpha2-3)Gal(beta1-4)Xyl-Np(beta1- as a potential inhibitor of human skin fibroblast glycosaminoglycan biosynthesis. This synthesis was achieved by sequential use of transglycosylating activities of Escherichia coli beta-galactosidase and Trypanosoma cruzi trans-sialidase. The structure of the oligosaccharide obtained was determined by HPLC, ion-spray mass spectrometry, and NMR.
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PMID:All-transglycolytic synthesis and characterization of sialyl(alpha2-3)galactosyl(beta1-4)xylosyl-p-nitrophenyl(beta1-), an oligosaccharide derivative related to glycosaminoglycan biosynthesis. 928 34

Mouse eggs fixed with paraformaldehyde were incubated with various exoglycosidases and their sperm-binding activities were examined. The number of sperm bound per egg was increased by sialidase treatment and decreased by beta-galactosidase treatment. No prominent reduction of sperm-binding was observed after alpha-galactosidase treatment. Mouse sperm also bound to asialofetuin-coupled agarose beads but not to fetuin-coupled beads. The sperm-binding was abolished when asialofetuin-gel was treated with beta-galactosidase specific to the beta 1-->4 linkage or N-Glycanase. Furthermore asialofetuin, but not beta-galactosidase-treated asialofetuin, competitively inhibited the binding of sperm to the zona pellucida of live eggs. These results suggest that mouse sperm recognize beta-galactose residues of the zona pellucida at the initial stage of the binding.
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PMID:Binding of mouse sperm to beta-galactose residues on egg zona pellucida and asialofetuin-coupled beads. 929 59

Cathepsin A [EC 3.4.16.1], so called protective protein, occurs as an enzyme complex with lysosomal beta-galactosidase [3.2.1.23] and is involved in the stable enzymic expression of lysosomal sialidase [3.2.1.18]. In this study we investigated the enzymatic properties of cathepsin A in the bovine beta-galactosidase complex and how it is involved in the molecular multiplicities of the beta-galactosidase and sialidase complexes. Bovine protective protein homologous to the human protein had a molecular weight of 48 kDa on SDS-PAGE and cathepsin A activity optimum around pH 6.0. It hydrolyzed dipeptide substrates composed of hydrophobic amino acids much faster than any other type of substrate tested. This specificity was found to be conserved from human to a non-mammal, chicken. Immunoprecipitation using an anti beta-galactosidase antibody demonstrated that cathepsin A is a component of both the sialidase and beta-galactosidase complexes. The over 700 kDa sialidase complex depolymerized by a brief incubation at pH 7.5 and the sialidase was inactivated irreversibly via formation of an enzyme active smaller species of sialidase. The 669 kDa beta-galactosidase complex dissociated reversibly into a 120 kDa beta-galactosidase and a 170 kDa cathepsin A, but the 120 kDa beta-galactosidase, free from the cathepsin A, formed a 260 kDa aggregate under the same conditions. Inactivation of cathepsin A by heat treatment did not affect its complex forming activity. The 170 kDa protective protein dissociated into a 50 kDa one at pH 7.5, which no longer formed the complex. These findings indicate that the 170 kDa protective protein could be the minimum unit required for in vitro reconstitution of the complex, and that its complex forming activity is carried in a heat-stable domain. Both beta-galactosidase and cathepsin A activities were labile under the dissociated condition, indicating that it physiologically stabilizes not only beta-galactosidase but also itself by forming the complex.
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PMID:Protective protein in the bovine lysosomal beta-galactosidase complex. 935 58

Lysosomal sialidase occurs in a multienzyme complex that also contains beta-galactosidase and cathepsin A. We previously cloned the human lysosomal sialidase cDNA and characterized mutations in human sialidosis patients. Here, we report the cloning and expression of the mouse lysosomal sialidase cDNA and gene. The 1.77 kb cDNA encodes an open reading frame of 408 amino acids which shows high homology to the human lysosomal sialidase (80%), the rat cytosolic sialidase (65%) and viral and bacterial sialidases (50-55%). The sialidase gene is approximately 4 kb long and contains six exons. The five introns range in size from 96 to 1200 bp. Northern blot analysis revealed high expression of multiple sialidase transcripts in kidney and epididymis, moderate levels in brain and spinal cord, and low levels in adrenal, heart, liver, lung and spleen. Transient expression of the cDNA clone in sialidase-deficient SM/J mouse fibroblasts and human sialidosis fibroblasts restored normal levels of sialidase activities in both cell types. Immunocytochemically expressed sialidase co-localized with a lysosomal marker, LAMP2, confirming its lysosomal nature. Since sialidase activity requires its association with beta-galactosidase and cathepsin A, the expression of mouse sialidase within human sialidosis cells underlines the structural similarity between mouse and human enzymes and suggests that the mechanism for complex formation and function is highly conserved.
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PMID:Cloning of the cDNA and gene encoding mouse lysosomal sialidase and correction of sialidase deficiency in human sialidosis and mouse SM/J fibroblasts. 938 11

Capitalizing on the readily available ganglioside, GM1, we have devised a simple synthesis of labeled GM1 analogues with sulfur in place of oxygen in their linkage to the ceramide residue (SGM1). The sugar moiety of ganglioside GM1 was released by ozonolysis and subsequent alkaline fragmentation in good yield. During acetylation of the ganglioside sugar, the carboxyl group of the sialic acid residue lactonized with the 2-hydroxyl group of the inner galactose moiety (galactose II). The resulting sialoyl-II2-lactone of pentadeca-O-acetyl-monosialogangliotetraose could be readily transformed into the alpha-glycosyl bromide. Subsequent treatment of this glycosyl bromide with potassium thioacetate afforded the sialoyl-II2-lactone of tetradeca-O-acetyl-1-S-acetyl-1-thio-beta-monosialogangliotetra ose. The latter could be condensed with (2R, 3R, 4E)-3-O-benzoyl-2-dichloroacetamido-1-iodo-4-octadecen -3-ol in methanolic sodium acetate to afford a protected lyso-SGM1 derivative. One-step removal of the protecting groups under alkaline conditions gave beta-monosialogangliotetraosyl thiosphingosine. This lyso-SGM1 was converted into labeled analogues of SGM1 using the N-succinimidoyl derivative of radiocarbon-labeled octanoic and octadecanoic acid, respectively. Subsequent actions of GM1-beta-galactosidase, beta-hexosaminidase A, sialidase and again GM1-beta-galactosidase on these labeled analogues of SGM1 in the presence of taurodeoxycholate produced the respective analogues of GM2, GM3, lactosylceramide and glucosylceramide, respectively.
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PMID:Synthesis of ganglioside GM1 containing a thioglycosidic bond to its labeled ceramide(s). A facile synthesis starting from natural gangliosides. 940 93


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