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)

We propose a three-dimensional (3-D) sugar-mapping technique for pyridylaminated (PA) neutral and sialyl oligosaccharides as a powerful structural characterization of N-linked oligosaccharides using only picomoles of samples. The new map consists of the elution data from 42 different sialyl oligosaccharides, 26 of which are mono-, 7 of which are di-, 7 of which are tri-, and 2 of which are tetra-sialylated oligosaccharides. The 20 standard sialyl oligosaccharides were released from human serum and calf fetuin by digestion with glycoamidase A. The other 22 standard sialyl oligosaccharides were obtained by subsequent digestion of the above 20 sialyl oligosaccharides with beta-galactosidase, beta-N-acetylhexosaminidase, alpha-fucosidase, and alpha 2-->3 specific sialidase. The present 3-D mapping method involves the following four steps: First, a neutral and sialyl PA-oligosaccharide mixture is separated by HPLC on the diethylaminoethyl (DEAE) column according to the sialic acid content, and the elution data are considered as one of the three dimensions (Z-axis). Then, neutral, mono-, di-, tri-, and tetra-sialyl oligosaccharides are individually separated on the octadecylsilyl (ODS)-silica (X-axis) and amide-silica (Y-axis) columns. The fourth step is to plot the coordinates on a two-dimensional (2-D) map. Thus, for each of the groups separated on the DEAE column, a 2-D map can be achieved. By repeating the whole process for each group of different sialylation, the layers of the 2-D map lined up on the Z-axis form a 3-D map.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Three-dimensional elution mapping of pyridylaminated N-linked neutral and sialyl oligosaccharides. 754 Mar 66

Morphological and histoenzymological differences have been observed between intercalated and principal cells of the quail Coturnix coturnix japonica collecting ducts. The present study was designed to shed light on the lectin affinity of the collecting duct cells within cortex and medulla by the use of HRP-labelled lectins combined with glycosidase degradation. Binding of PNA and RCA-I lectins consequent to enzymatic release of sialic acid revealed abundant sialylated carbohydrate moieties within the principal cell cytoplasm. This characteristic binding pattern differed considerably from the staining observed in the intercalated cells. Interesting information also emerged about the presence of sialoglycoconjugates having the terminal disaccharide sialic acid-beta-N-acetylgalactosamine originating from the increased SBA binding and the unmodified DBA labelling after removal of sialic acid. Sequential degradation by sialidase/beta-galactosidase followed by incubation with DBA offered the possibility to suspect that the receptor sugar for the penultimate beta-galactose may be N-acetylgalactosamine. Conversely, we were not able to define the accept sugar for penultimate beta-GalNAc owing to the lack of availability of beta-N-acetylgalactosaminidase enzyme. When although further studies are clearly needed to elucidate the physiological role of the cellular sialoglycoconjugates detected, the present results already provide valuable insight into the carbohydrate composition of intercalated and principal cells in the quail collecting ducts.
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PMID:Mosaic lectin labelling in the quail collecting ducts. 754 Dec 64

Epstein-Barr virus (EBV)-transformed human B-cell lines, L-KT9 and DH3 cells express CD23 antigen, and grow in a mixture of single and aggregated cells. The CD23 molecule has high amino acid sequence homology with C-type lectin and recently we have shown that the solubilized CD23 molecule can really interact with galactose residues on glycoproteins. In this study, therefore, we tested whether CD23 antigen on the cell surface really acts as a galactose-binding lectin in the aggregation of these cells. The EBV-transformed cells (L-KT9) were separated into an aggregated-cell-rich fraction and a single-cell-rich fraction. Aggregated cells disaggregated after removal of galactose by beta-galactosidase treatment, whereas single cells made large aggregation on sialidase treatment, and this aggregation was inhibited in the presence of asialo-fetuin. On the other hand, naturally aggregated cells become single cells with anti-CD23 monoclonal antibody (mAB) as well as the soluble form of CD23, but not with anti-CD21 mAB. In addition, L-KT9 and DH3 cells bound to asialo-fetuin-coupled Sepharose (ASF-Sepharose) and this binding was significantly inhibited by pre-treatment of cells with anti-CD23, but not with anti-CD21 or other anti-adhesion molecules. From these results, we conclude that the naturally aggregated state of EBV-transformed cells occurs mainly through the interaction of CD23 as a lectin molecule and galactose residues as its ligand.
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PMID:CD23 molecule acts as a galactose-binding lectin in the cell aggregation of EBV-transformed human B-cell lines. 757 99

Glycophorin A was digested with glycoprotease (Pasteurella haemolytica) and the digest was fractionated by a combination of high-pressure column chromatographies to produce the glycopeptides GPA-1 to GPA-6. Sequence analysis of the glycopeptides revealed that two serine residues (Ser-14 and Ser-15) are not glycosylated, Thr-17 and Ser-19 being glycosylated instead, in disagreement with the accepted structure. The glycopeptides thus obtained were treated with sialidase and beta-galactosidase. The Tn antigenicity, as assayed by the binding to a monoclonal anti-Tn antibody (MLS 128), was found exclusively in the glycopeptides including three (cluster I) or four (cluster II) consecutive residues of GalNAc-Ser/Thr, whereas the glycopeptide (GPA-2) containing two nonconsecutive GalNAc-Ser/Thr residues had practically no Tn antigenicity. The immunoreactivities of GPA-1 and GPA-3, containing both clusters I and II, and GPA-4, containing cluster II, were 63% (calcd. 67%), 81% (calcd. 86%), and 50% (calcd. 50%), respectively, of the immunoreactivity of GPA-5 or GPA-6, containing cluster I (the average being taken as the basis), based on the reactivity per GalNAc residue. These results indicate that clusters I and II react with the antibody to the same extent. The structure consisting of three consecutive glycosylated Ser/Thr residues may be essential for Tn antigenicity in the light of previous results for ovine submaxillary mucin.
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PMID:Epitopic structure of Tn glycophorin A for an anti-Tn antibody (MLS 128). 768 97

The outer surface of mouse B lymphocytes carries constitutive and inducible beta-galactosidase isozymes. A brief (30 min) treatment of B lymphocytes with lysophosphatidylcholine (lyso-Pc) immediately induced an approximate 3-fold higher beta-galactosidase activity than the constitutive isozyme of untreated B lymphocytes. Thus, the lyso-Pc-inducible isozyme is not a de novo enzyme. Outer surface of mouse T lymphocytes carries constitutive (non-Neu-1) and inducible (Neu-1) sialidase isozymes. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and the Neu-1 sialidase of T lymphocytes were required for conversion of vitamin D3-binding protein (Gc protein) to a potent macrophage activating factor. This enzymatic generation of the macrophage activating factor was mediated via enzyme-associated receptors.
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PMID:Roles of beta-galactosidase of B lymphocytes and sialidase of T lymphocytes in inflammation-primed activation of macrophages. 772 26

The receptor protein for thyrotrophin (thyroid-stimulating hormone; TSH) is associated with a glycosphingolipid moiety. The protein belongs to the family of receptors that couple to guanine nucleotide binding proteins; the glycosphingolipid contains sialic acid and belongs to the family of gangliosides. This report defines the structure of the receptor ganglioside in the Fisher rat thyroid cell line (FRTL-5). Receptor protein was purified by TSH affinity chromatography from FRTL-5 cells, biosynthetically labelled with [3H]galactose and [3H]glucosamine, and resolved by SDS-PAGE. A single radiolabelled band of Mr approximately 80 kDa, corresponding to the predicted size of the cloned receptor, contained ganglioside. Gangliosides were extracted from unlabelled receptor protein after SDS-PAGE and probed on TLC plates with 125I-labelled Limax flavus agglutinin or the B subunit of cholera toxin, before and after digestion with Vibrio cholerae sialidase or beta-galactosidase. The TSH receptor (TSH-R) ganglioside belongs to the gangliotetraose family, having sialic acid attached to both galactose molecules. Its sialic acid is devoid of negative charge because of the formation of internal esterlactones. Its structure is lactonized N-acetylneuraminyl-(alpha 2-->3)galactosyl(beta 1-->3)-N-acetylgalactosaminyl(beta 1-->4)-[N-acetylneuraminyl(alpha 2-->3)]galactosyl(beta 1-->4)glucosyl(beta 1-->1)ceramide (GDla-lactone). Ganglioside lactones have not been previously described as components of thyroid cells. They are highly rigid and are more likely than their parent structures to serve as molecular recognition sites and elicit immunoreactivity. Identification of this unique ganglioside intimately associated with the TSH receptor implies that it has an integral role in receptor structure and function.
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PMID:Characterization of ganglioside associated with the thyrotrophin receptor. 773 42

Four different insect cell lines that can be used as hosts for baculovirus infection were assayed for the presence of endogenous exoglycosidases. All four cell lines, derived from Spodoptera frugiperda, Trichoplusia ni, Bombyx mori, or Malacosoma disstria, contained N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-galactosidase, and sialidase activities. Exoglycosidase activities were found in cell lysates as well as cell-free supernatants from uninfected and wild-type baculovirus infected cells. Oligosaccharide analysis of cellular glycoproteins using lectins recognizing Gal beta 1, 3GalNAc, Gal beta 1, 4GlcNAc, and NeuAc alpha 2,6Gal demonstrated that only Gal beta 1,3GalNAc was present. The demonstration that these cells contain exoglycosidases raises the possibility that the oligosaccharides of baculovirus-expressed glycoproteins are subject to enzymatic degradation.
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PMID:Insect cell hosts for baculovirus expression vectors contain endogenous exoglycosidase activity. 776 90

To probe the potential for extracellular degradation of glycoprotein oligosaccharides in conjunction with Chinese hamster ovary (CHO) cell culture, an initial characterization of several CHO cell glycosidases was performed using 4-methylumbelliferyl substrates. CHO cell lysates contained sialidase, beta-galactosidase, beta-hexosaminidase, and fucosidase activities with pH optimums near 5.5, 4, 6, and 6.5, respectively. These glycosidase activities were also present in cell-free supernatant samples from commercial CHO cell cultures. The sialidase activity was further characterized. In contrast to previous reports concerning mammalian sialidases, the sialidase activity in CHO cell lysate retained considerable activity at pH 7 and was very stable, with a half-life of 57 h at 37 degrees C. Both the Km and Vmax of CHO lysate sialidase for 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid (4MU-NeuAc) varied with pH, and this activity was competitively inhibited by 2,3-dehydro-2-deoxy-N-acetylneuraminic acid and by free N-acetylneuraminic acid. The kinetic characteristics and pH-activity profiles of the CHO cell lysate and cell culture supernatant sialidase activities were essentially identical, and both released sialic acid from the glycoprotein fetuin at pH 7.5. These results suggest that the oligosaccharides of glycoproteins secreted by CHO cells can potentially be modified extracellularly by sialidase under culture conditions which promote the release and extracellular accumulation of this enzyme.
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PMID:Glycosidase activities in Chinese hamster ovary cell lysate and cell culture supernatant. 776 7

Two IgM lambda cold agglutinins (CAs) reacted with protease- and sialidase-resistant antigens expressed in equal strength on human adult (I), newborn (i), i adult, rabbit (I) and rhesus monkey (i) erythrocytes. The antibodies were inhibited by the linear type 2 sequence lacto-N-neotetraose and the branched type 2 sequence lacto-N-neohexaose. Endo-beta-galactosidase treatment of red cells, which splits type 2 chains from the surface, abolished CA reactivity. The CAs expressed the idiotype recognized by the anti-idiotype 9G4 specific for anti-I and anti-i CAs. The data suggest that the two CAs recognize linear (i) as well as branched (I) type 2 chains. It is proposed to term these CAs anti-j.
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PMID:Anti-j: human cold agglutinins recognizing linear (i) and branched (I) type 2 chains. 780 15

The mucin-type carbohydrate Tn cryptantigen (GalNAc alpha 1-O-Ser/Thr, where GalNAc is N-acetyl-D-galactosamine) is expressed in many carcinomas, in haemopoietic disorders including the Tn syndrome, and on human immunodeficiency virus (HIV) coat glycoproteins, but is not expressed on normal, differentiated cells because of the expression of a Tn-processing galactosyltransferase. Using Jurkat T leukaemic cells which express high levels of Tn antigen due to deficient Tn galactosylation, we have established the Tn antigen-mediated gene transfer and demonstrate the considerable efficiency of this approach. We used poly(L-lysine) conjugates of the monoclonal antibody 1E3 directed against the Tn antigen to deliver the luciferase and beta-galactosidase reporter genes to Jurkat cells by receptor-mediated endocytosis. Addition of unconjugated 1E3 reduced transfection efficiency in a concentration-dependent manner and incubation with free GalNAc abolished DNA transfer completely, indicating that gene delivery is indeed mediated by the Tn antigen. Pre-treatment of Jurkat cells with Vibrio cholerae sialidase, which uncovers additional Tn antigens, resulted in an improvement of gene transfection. Both human and chicken adenovirus particles attached to the DNA/polylysine complex strongly augmented transgene expression. When the beta-galactosidase (lacZ) gene was delivered to Jurkat cells by Tn-mediated endocytosis, up to 60% of the cells were positive in the cytochemical stain using 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) as a chromogenic substrate. The efficiency of the transferrin receptor-mediated DNA uptake into Jurkat cells was comparatively low, although these cells were shown to express considerable amounts of transferrin receptor. We show here that a mucin-type carbohydrate antigen mediates highly efficient DNA uptake by endocytosis into Jurkat T cells. This method represents a 50-fold improvement of Jurkat cell transfection efficiency over other physical gene transfer techniques. Specific gene delivery to primary cancer cells exhibiting Tn epitopes may especially be desirable in immunotherapy protocols.
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PMID:Carbohydrate receptor-mediated gene transfer to human T leukaemic cells. 782 4


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