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)

The gene encoding a beta-galactosidase from Xanthomonas manihotis was cloned into Escherichia coli. The gene resides on a 2.4 kb DNA fragment which was isolated from a partial Sau3A library in the cloning vector pUC19 using 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) as the selection. The enzyme produced by the clone has a specificity for beta 1-3- > beta 1-4-linked galactose. The nucleotide sequence of the gene was determined. The deduced protein sequence contained 597 amino acids yielding a monomeric molecular mass of 66 kDa. The cloned beta-galactosidase showed no similarity to any known prokaryotic beta-galactosidase. However, extensive similarity was observed with eukaryotic beta-galactosidases from animals, plants and fungi. The strongest similarity was with the beta-galactosidases found in the human and mouse lysosomes (42 and 41% identity, respectively). Alignment of the X.manihotis and eukaryotic beta-galactosidase sequences revealed seven highly conserved domains common to each protein. Additionally, Domain 1 in X.manihotis showed similarity to regions within catalytic domains from seven xylanases and cellulases belonging to family 10 of glucosyl hydrolases. A region spanning Domain 2 showed similarity to the catalytic domain of endo beta 1-3 glucanases from tobacco and barley.
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PMID:A novel beta-galactosidase gene isolated from the bacterium Xanthomonas manihotis exhibits strong homology to several eukaryotic beta-galactosidases. 856 48

A novel sulphotransferase (sulpho-T) activity from rat colonic mucosa was characterized using O-glycan core 1 substrate, Gal beta 1-3GalNAc alpha-benzyl. Derivatives of Gal beta 1-3GalNAc- were used to demonstrate that the 3- and 4-hydroxyl of Gal and the 2-acetamido group of the GalNAc residue of Gal beta 1-3GalNAc alpha-benzyl substrates were important for activity. Sulphated product using Gal beta 1-3GalNAc alpha-benzyl as substrate was analysed by ion spray mass spectrometry, methylation analysis, high-pH anion-exchange chromatography and beta-galactosidase digestion. The results suggested that sulphate was added to the 3-position of the Gal residue. The synthesis of core 2 from core 1 by UDP-GlcNAc: Gal beta 1-3GalNAc beta 6-GlcNAc-transferase was inhibited by sulphation of the Gal residue, indicating that GlcNAc beta 1-6 branching has to precede sulphation in the O-glycan core 1 processing pathway. These data demonstrate several novel pathways in the synthesis of sulphated mucin-type oligosaccharides.
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PMID:Characterization of a novel mucin sulphotransferase activity synthesizing sulphated O-glycan core 1,3-sulphate-Gal beta 1-3GalNAc alpha-R. 860 71

The synthesis of N-acetyllactosamine (D-Galp beta 1-4D-GlcpNAc) with very low contamination of its isomer N-acetyllactosamine (D-Galp beta 1-6D-GlcpNAc) was obtained by use of regioselective transglycosylation activity of beta-galactosidase from Bacillus circulans using lactose as the donor of D-Galp and D-GlcpNAc as the acceptor. The reaction was conducted at 15 degrees C and at pH 5.0. The incubation time was considerably reduced and the yield improved 100% with respect to the best results so far described in the literature.
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PMID:High-yield synthesis of N-acetyllactosamine by regioselective transglycosylation. 861 28

Transforming growth factor-beta 1 (TGF-beta 1) is known to regulate cardiac cell function and its overexpression in the heart is thought to contribute to the development of cardiac hypertrophy and fibrosis. We wished to develop a high efficiency gene transfer method that could be used both in vitro and in vivo and result in the overexpression of TGF-beta 1. For this purpose, we constructed a replication-deficient human adenovirus 5 vector encoding for human TGF-beta 1 and used for control purposes an adenovirus lacZ vector. The adenovirus 5 construct was capable of infecting neonatal rat cardiac myocytes, fibroblasts and VSMCs. Of the three cell types, cardiac myocytes appear more susceptible to infection by the adenovirus 5 construct as assessed through beta-galactosidase staining. Infection of cardiac fibroblasts, myocytes and VSMCs with the hTGF-beta 1 adenovirus leads to the expression of hTGF-beta 1 mRNA and enhanced levels of bioactive and total TGF-beta 1 protein. Infection with hTGF-beta 1 adenovirus also results in enhanced levels of collagen type III gene expression in VSMCs and fibroblasts whereas in cardiac myocytes it leads to increased levels for sarcomeric and beta-actin. Thus, this adenoviral vector might be used for the exploration of in vivo effects of altered levels of cardiac TGF-beta 1.
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PMID:Adenovirus-mediated overexpression of human transforming growth factor-beta 1 in rat cardiac fibroblasts, myocytes and smooth muscle cells. 873 1

The fucosyltransferases constitute a family of glycosyltransferases incorporating fucose residues into glycoprotein or glycolipid glycans. They afford one of the possible termination steps of glycoconjugate biosynthesis creating the sialyl Lewisx or sialyl Lewisa determinant, which play an important role in cell-cell interaction. While cDNA, chromosomal localization and kinetic properties of a number of fucosyltransferases are known, immunocytochemical localization and trafficking studies have been delayed because of the lack of specific antibodies due to the pronounced homology of alpha 1, 3 fucolsyltransferases III, V and VI. Here we report development and characterization of monospecific polyclonal antibodies to alpha 1-3 fucosyltransferase V (FucT-V) and their application for immunodetection in transfected cells. Antisera against FucT-V were raised in two different ways: first by producing a fusion protein beta-galactosidase-FucT-V in Escherichia coli, and by synthesizing a peptide stretch specific for FucT-V. Polyclonal antisera were raised against each of both antigens and characterized by enzyme-linked immunosorbent assay, neutralization of activity, immunoblotting, immunofluorescence and immunoprecipitation of metabolically labeled COS cells, transiently transfected with cDNA encoding FucT-V. Both antibodies recognized only FucT-V. No cross-reactivity to FucT-III or FucT-VI was observed. FucT-V was localized mainly to the Golgi apparatus by colocalization with beta 1, 4-galactosyltransferase, and to the cell surface of COS, CHO and HeLa cells. Expression of FucT-V in COS cells revealed three enzyme forms of 58, 53 and 50 kDa, respectively. These size differences arose by post-translational modifications, as shown by pulse-chase experiments. Our results indicate that alpha 1-3 fucosyltransferase is a Golgi-associated enzyme and suggest its possible occurrence on the cell surface.
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PMID:Immunodetection of alpha 1-3 fucosyltransferase (FucT-V). 873 18

The characteristics of the binding of human lactoferrin (LF) to the cells of a human monocytic leukemia cell line, THP-1, were investigated. 125I-Labeled LF (125I-LF) bound to THP-1 cells, and the binding increased markedly as the cells matured into macrophages (THP-1 macrophages) by stimulation with phorbol 12-myristate 13-acetate. Scatchard analysis of the binding of 125I-LF to THP-1 macrophages indicated that high and low affinity receptor sites (Kd = 0.57 x 10(-6) and 3.7 x 10(-6) M, respectively) are present on the cells. The number of these high and low affinity receptor sites were 2.4 x 10(6), and 2.5 x 10(6) per cell, respectively. Removal of iron from 125I-LF did not affect its binding to THP-1 macrophages, indicating that the binding is not dependent on Fe(III) ion. The binding of the labeled LF to THP-1 macrophages was markedly decreased following acetylation, suggesting that the amino residues of the polypeptide portion of LF play a major role in the binding. The binding of labeled LF was partially inhibited by the isolated whole oligosaccharides of LF, and by the isolated whole oligosaccharides of band 3 glycoprotein of human erythrocyte membrane which contain poly-N-acetyllactosaminyl saccharide chains, like the LF oligosaccharides. Their inhibitory activity did not depend on the terminal sialyl residues of the saccharide chains. Lacto-N-fucopentaose III and lacto-N-neotetraose, an analogous structure being present in the poly-N-acetyllactosaminyl chains of LF, also artially inhibited the binding of 125I-LF to the THP-1 macrophages. When poly-N-acetyllactosaminyl saccharide chains of 125I-LF were cleaved by endo beta-galactosidase, the binding of 125I-LF was partially reduced. These results suggest that binding of LF to THP-1 macrophages is primarily mediated by its protein component, but a short oligosaccharide structure, possibly Gal beta 1-4GlcNAc beta 1-3Gal, which is contained in the nonreducing terminal region of poly-N-acetyllactosaminyl saccharide chains of LF and band 3, and in lacto-N-fucopentaose III and lacto-N-neotetraose is also recognized by THP-1 macrophages, and this recognition partly contributes to the binding of LF to cells.
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PMID:Binding characteristics of human lactoferrin to the human monocytic leukemia cell line THP-1 differentiated into macrophages. 885 Mar

Serum alpha-fetoprotein (AFP) is a glycoprotein of which the sugar chain is considered to show structural changes with malignancies. Microheterogeneity of the serum AFP carbohydrate structure was studied in samples from 35 patients with benign and malignant diseases. Sera were digested directly, extensively, and sequentially with sialidase. beta-galactosidase and beta-N-acetylhexosaminidase. Before and after digestion, sera were examined by means of lectin affinity electrophoresis using eight lectins. Relationships between AFP carbohydrate structures and liver diseases were elucidated by the lectin-reactive profiles and the effect of glycosidase digestion. More than 94% of the AFP carbohydrate structures found in patients with benign and malignant liver diseases were biantennary complex-type oligosaccharides. Changes in the AFP carbohydrate structures at the early stage of hepatocellular carcinoma revealed the addition of alpha 1-->6 fucose to the reducing terminal N-acetylglucosamine and monosialylated AFPs. In both advanced hepatocellular carcinoma and AFP producing extrahepatic malignancies, AFP carbohydrate structures were characterized as the further addition of beta 1-->4 N-acetylglucosamine and heterogeneity in the galactose and N-acetylglucosamine residues. Sequential glycosidase digestion and lectin affinity electrophoresis is useful for analysing the carbohydrate structures of serum glycoprotein.
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PMID:Comparison of carbohydrate structures of serum alpha-fetoprotein by sequential glycosidase digestion and lectin affinity electrophoresis. 889 7

Diffuse invasion of brain tissue by single tumor cells is a characteristic feature of gliomas and a major reason why these tumors cannot be completely resected. The molecular basis of brain invasion is poorly understood. We regulated the expression of beta 1 integrins, the major group of extracellular matrix receptors, in astrocytic tumor cells by using a tetracycline-dependent transcription control system. Rat C6 glioma cells were stably transfected with (a) the tetracycline-controlled transactivator (tTA) gene, (b) antisense beta 1 cDNA under the control of a tTA/tetracycline-responsive promoter, and (c) the beta-galactosidase (lacZ) gene for histochemical identification. In one clone, C6TL beta, beta 1 protein levels were unaffected in the presence of tetracycline, but they were reduced by 60% in the absence of tetracycline because of production of antisense mRNA. C6TL beta cells were transplanted into the striatum of nude mice. After 14 days in the presence of tetracycline in the drinking water, tumors showed diffuse brain invasion, mainly along vascular basement membranes. In the absence of tetracycline, however, tumor cells were compact and generally well delineated from the surrounding brain tissue. These data, ie, blocking of brain invasion by antisense beta 1 mRNA, either because of disturbed interaction of beta 1 with brain extracellular matrix components or interference with beta 1-dependent signaling pathways, strongly suggest that beta 1 integrins are required for diffuse brain invasion of gliomas.
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PMID:Diffuse brain invasion of glioma cells requires beta 1 integrins. 897 77

Thyroid hormone, acting through thyroid hormone receptors (TRs), plays an important role in amphibian metamorphosis and vertebrate development. To identify where and when TR beta 1 promoter is activated during fetal life, we carried out an in vivo functional study of a 1.3 kilobase (kb) TR beta 1 gene promoter using transgenic mice that express the beta-galactosidase gene under control of the TR beta 1 promoter. Transactivation of the gene was determined by blue staining of tissues after incubation with X-gal. High expression of transgene was detected in the limbs and face of the 12.5-day-old fetus (12.5 F) and 14.5 F, reminiscent of the changes occurring during amphibian metamorphosis, and this disappeared at 17.5 F. The expression was confined to the tip of finger bones, between fingers in the limb buds, and was detected in the root of whisker follicles, nose, and around the eyes. Signal was detected in the oral cavity, nasal cavity, lung, and urogenital sinus of 14.5 F, and disappeared at 17.5 F. Signal was detected in the midbrain and auditory vesicles of 9.5 F but was reduced between 12.5F and 17.5F, and there was no expression in the cerebral cortex layer of 0 days old neonates (PO). Expression was detected in the cortex after P5. There was signal in the cerebral cortex, cerebellum, kidney, and liver of adult mice. TR beta 1 messenger RNA was detected by RT-PCR in the developing limbs and face. Transgene expression in the interdigital tissues, which regress during development, suggests that TR beta 1 is expressed in mammals in areas undergoing apoptosis as well as in areas undergoing differentiation.
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PMID:Thyroid hormone receptor beta 1 expression in developing mouse limbs and face. 904 36

GlcNAc beta 1-2Man and GlcNAc beta 1-6Man were synthesized using the reverse hydrolysis activity of beta-N-acetylglucosaminidase from both jack beans and Bacillus circulans. In turn, Gal beta 1-4GlcNAc beta 1-2Man and Gal beta 1-4GlcNAc beta 1-6Man were synthesized regioselectively using the transglycosylation activity of beta-galactosidase from Diplococcus pneumoniae and B. circulans, respectively. These di- and trisaccharides are important components of complex type sugar chains and will be used as intermediates in our synthetic studies.
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PMID:Enzymatic syntheses of GlcNAc beta 1-2Man and Gal beta 1-4GlcNAc beta 1-2Man as components of complex type sugar chains. 907 16


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