Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A soluble UDP-Gal: Gal (alpha 1-3) galactosyltransferase was first detected in bovine colostrum and this enzyme activity was simply assayed by using rho-nitrophenyl-beta-lactoside (Gal(beta 1-4)Glc-C6H5NO2, rho NP-lactoside) as an acceptor. Treating the radioactive product with alpha- or beta-galactosidase, the radioactivity (greater than 95%) was released by only alpha-galactosidase and was identified as [3H]galactose. This shows that galactosyl residue was alpha-linked to rho-nitrophenyl-beta-lactoside. Methylation, hydrolysis, thin layer chromatography and fluorography of the reaction product (Gal(alpha 1-)-[3H]Gal(beta 1-4)Glc-rho NP) yielded 2,4,6-tri-O-methyl[3H]galactose, indicating that galactosyl residue had been transferred to the carbon-3 position of the terminal nonreducing beta-galactosyl residue in rho-nitrophenyl-beta-lactoside. These results confirmed that the structure of the reaction product was Gal(alpha 1-3)Gal(beta 1-4)Glc-rho NP. The enzyme requires Mn2+ for its activity, and shows pH optimum from 6.5 to 7.5. rho-Nitrophenyl-beta-lactoside and asialo alpha 1-acid glycoprotein were more effective as an acceptor than N-acetyllactosamine. The bovine colostrum (alpha 1-3) galactosyltransferase could not convert human O red cells into B active cells, indicating that this enzyme preparation did not contain the activity to synthesize human blood group B erythrocytes.
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PMID:Identification of a soluble UDP-Gal: Gal (beta 1-4)Glc (or GlcNAc) (alpha 1-3) galactosyltransferase of bovine colostrum. 251 15

Carbodiimide-mediated coupling of p-aminophenyl glycosides to a naturally nonglycosylated enzyme yields a neoglycoenzyme. This compound combines inherent enzymatic activity with synthetically conferred ligand properties to lectins. Appropriate choice of the ligand allows custom-made synthesis to reliably detect various types of lectins. To exemplify practical applications of this class of compounds, glycosylated bacterial beta-galactosidase has been employed to quantitate plant lectins, immobilized on plastic surfaces as well as on nitrocellulose. Competitive inhibition by specific sugar ascertained the dependence of binding on protein--carbohydrate interactions. In view of lectins as tools, a sandwich lectin-binding assay for high mannose-type glycoprotein detection has been modified to principally facilitate wide application to other lectin-reactive sugar chains by introducing the neoglycoenzyme. In addition to lectin determination in solid-phase assays, neoglycoenzymes allow one to glycohistochemically localize endogenous lectins in tissue prints and tissue sections with a minimum number of steps. This nonradioactive, rapid, sensitive, and convenient assay concept, based on conjugation of a ligand to an enzyme with maintenance of its receptor-binding activity, may find extended application beyond lectinology in receptor analysis.
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PMID:Neoglycoenzymes: a versatile tool for lectin detection in solid-phase assays and glycohistochemistry. 251 14

Oligopeptides of the highly conserved herpes virus glycoprotein B (gB) were expressed from DNA fragments of the EBV gB (BALF4) and HSV-2 gB open reading frames as fusion proteins with the lambda CII protein and beta-galactosidase (GZ), respectively, in Escherichia coli. After immunopurification using anti-gB or anti-GZ affinity columns, the fusion proteins were used in vitro to stimulate human peripheral blood lymphocytes (PBL) or murine lymph node cells that have been primed with EBV, HSV-1, HSV-2, VZV or HCMV (all human herpes viruses) to proliferate. Results obtained in BALB/c mice indicate that different herpes viruses induce different levels of T-cell response to each other and to gB, over a range of type-specific and cross-reactive T-cell epitopes. There is a lack of correlation of immunogenicity and antigenicity in the generation of T-cell responses between some of the viruses. Major T-cell epitopes are located at the C terminal half of the gB molecule. The T-cell response to gB in healthy individuals seropositive for various combinations of the five herpes viruses differed markedly from individual to individual, even when they are seropositive to the same set of herpes viruses. However, two individuals with high proliferative T-cell response to VZV and sharing HLA A2, B7, DR2 and DQw1 are also good responders for cross-reactive gB/fragments and for virus antigen of all the five herpes viruses. Therefore the data obtained demonstrated that the MHC and the immune interaction arising from cross-reactive T-cell response evoked by other herpes viruses may determine the pathogenesis of a herpes virus infection.
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PMID:Proliferative T-cell response to glycoprotein B of the human herpes viruses: the influence of MHC and sequence of infection on the pattern of cross-reactivity. 255 84

Procyclin, a glycoprotein surface antigen of procyclic forms of Trypanosoma brucei, was expressed in Escherichia coli as a cro-beta-galactosidase fusion protein. Antibodies produced in rabbits immunised with gel-purified fusion protein bound to the surface of living procyclic culture forms in indirect immunofluorescence assays and were able to immunoprecipitate procyclin from lysates of trypanosomes biosynthetically labelled with tritiated proline. In addition, the antibodies recognised synthetic peptides corresponding to three different regions of the procyclin molecule, including a glutamic acid-proline dipeptide repeat. The results indicate that T. brucei procyclin expressed as a fusion protein is immunogenic and antigenically intact. In contrast, no rabbit antibodies could be produced against a 16-amino-acid synthetic peptide consisting of the dipeptide repeat, even when the peptide was coupled to carrier proteins.
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PMID:Expression of Trypanosoma brucei procyclin as a fusion protein in Escherichia coli. 265 16

The sandwich-type immunometric assay was modified by replacing the solid phase-bound antibody with a lectin for the determination of glycoproteins carrying terminal N-acetylglucosamine residues. Microwells were coated with Bandeiraea simplicifolia II lectin and incubated with glycosylation variants of human serum glycoproteins. The bound glycoproteins were detected by time-resolved fluorometry using europium-labeled antibodies. Agalacto-derivatives of alpha 1-acid glycoprotein and transferrin obtained by neuraminidase and beta-galactosidase treatment bound to the immobilized lectin, whereas the native or desialylated glycoproteins showed no binding. The measuring range of the method for agalacto-alpha 1-acid glycoprotein was 0.01 to 10 micrograms/ml and for agalacto-transferrin 1 to 300 micrograms/ml. The binding of the agalacto-glycoproteins was totally inhibited with 1 to 10 mM N-acetylglucosamine which confirmed the specificity of the method for glycoproteins containing terminal N-acetylglucosamine residues. The results indicate that the novel lectin-immunofluorometric method is sensitive and has a wide measuring range for the determination of glycosylation variants of glycoproteins.
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PMID:A lectin-immunofluorometric assay using an immobilized Bandeiraea simplicifolia II lectin for the determination of galactosylation variants of glycoproteins. 265 80

Human intestinal bacteria were grown in a 3-stage continuous culture system on a medium containing complex polysaccharides and proteins as carbon and nitrogen sources. Selected bacterial populations were enumerated and glycosidase, protease and arylamidase activities measured. Comparison of arylamidase and glycosidase activities in the multichamber system (MCS) and faeces showed that the predominant faecal enzymes were also produced by bacteria growing in the MCS. After 48 d operation, porcine gastric mucin (5.8 g/d) was independently fed to vessel 1. Elevated levels of volatile fatty acid (VFA) formation showed that the glycoprotein was actively fermented. The increase in carbohydrate availability as a result of breakdown of the mucin oligosaccharides stimulated bacterial growth and activities. The enzymological measurements showed that mucin increased production of both cell-bound and extracellular glycosidases, such as beta-galactosidase, alpha-glucosidase and N-acetyl-beta-glucosaminidase. Protease activities were profoundly influenced by mucin. These were largely cell-bound in non-mucin cultures but were predominantly extracellular and collagenolytic when mucin was present. Experiments with protease inhibitors showed that cysteine proteases were the major cell-bound and extracellular enzymes in both mucin and non-mucin cultures, but that serine and metalloproteases were also present. The effect of mucin on arylamidase formation was less marked, although there was increased production of these enzymes in vessels 1 and 2 of the MCS. These results suggest that host-produced substances such as mucin glycoprotein may play a role in modulating the growth and activity of bacteria growing in the human large intestine.
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PMID:Influence of mucin on glycosidase, protease and arylamidase activities of human gut bacteria grown in a 3-stage continuous culture system. 266 79

We have developed an ELISA which detects, with high specificity, antibodies against a major surface protein of P. falciparum merozoites which is a processing product of the precursor glycoprotein gp190. This assay can be used in the diagnosis of acute malaria in individuals with primary infection. Two partial sequences of gp190 were expressed in E. coli as beta-galactosidase (beta-Gal) fusion proteins. The same sequences fused to chloramphenicol acetyltransferase (CAT) or mouse dihydrofolate reductase (DHFR) react with high frequency when sera of acute malaria patients are analyzed in immunoblots. Antibodies from such sera crosslink, via their antigen binding sites, the beta-Gal fusions to the corresponding CAT or DHFR fusions adsorbed to a solid phase as demonstrated by the captured beta-Gal activity. The assay is highly specific, shows extremely low cut off values and should therefore be widely applicable.
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PMID:A new tool for the serodiagnosis of acute Plasmodium falciparum malaria in individuals with primary infection. 266 17

Glycoproteins located on the luminal surface of the plasma membrane of tick gut epithelial cells, when used to vaccinate cattle, are capable of stimulating an immune response that protects cattle against subsequent tick infestation. One such tick gut glycoprotein, designated Bm86, has been purified to homogeneity and the amino acid sequences of peptide fragments generated by endoproteinase Lys-C digestion have been determined. We report here the isolation and characterization of a cDNA that encodes Bm86. The nucleotide sequence of the cDNA contains a 1982-base-pair open reading frame and predicts that Bm86 contains 650 amino acids including a 19-amino acid signal sequence and a 23-amino acid hydrophobic region adjacent to the carboxyl terminus. The main feature of the deduced protein sequence is the repeated pattern of 6 cysteine residues, suggesting the presence of several epidermal growth factor-like domains. A fusion protein consisting of 599 amino acids of Bm86 and 651 amino acids of beta-galactosidase was expressed in Escherichia coli as inclusion bodies. Ticks engorging on cattle vaccinated with these inclusion bodies were significantly damaged as a result of the immune response against the cloned antigen.
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PMID:Cloning and expression of a protective antigen from the cattle tick Boophilus microplus. 269 68

A partial cDNA clone [2.4 kilobase (kb)] for the nerve growth factor-inducible large external (NILE) glycoprotein was selected from a lambda gt11 expression library constructed using mRNA from PC 12 cells. A 0.2 kb subclone (pNILE-1B) was used for Northern blot analysis of NILE message present in 2 NILE-positive neuronal cell lines and 2 NILE-negative glial cell lines. pNILE-1B hybridizes with components of 6.8 and 2.0 kb in the 2 neuronal cell lines but fails to show hybridization with any components in the 2 glial cell lines. Only the 6.8 kb species would be large enough to code for the NILE polypeptide. A rabbit antiserum was prepared against the NILE-beta-galactosidase fusion protein produced by the NILE clone. This antiserum (anti-NILE-beta-gal) immunoprecipitates NILE glycoprotein from neuronal cell lines, further confirming the authenticity of the NILE cDNA clone. The epitope recognized by anti-NILE-beta-gal is contained in an 85 kDa tryptic fragment from the phosphorylated carboxy terminus of NILE. The 160 kDa tryptic fragment containing the amino terminus is not recognized by anti-NILE-beta-gal. Both immunoprecipitation and immunofluorescence experiments indicate that the anti-NILE-beta-gal epitope is not exposed on the cell surface but is accessible only after cells are treated with detergent. The cytoplasmic nature of the determinant is also indicated by its absence on a truncated, soluble form of NILE released from cells (possibly by a proteolytic mechanism) into the medium. This released NILE is 15-20 kDa smaller than the detergent-extracted NILE and, in addition to lacking the anti-NILE-beta-gal epitope, does not contain the cytoplasmic site(s) of phosphorylation. Nucleotide sequencing of the pNILE-1B subclone confirms the location of the anti-NILE-beta-gal epitope in the cytoplasmic domain. The clone contains an open reading frame coding for a 79 amino acid segment of the polypeptide that differs in only 2 residues from the cytoplasmic domain of the L1 glycoprotein.
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PMID:Characterization of a partial cDNA clone for the NILE glycoprotein and identification of the encoded polypeptide domain. 272 51

A 646 bp fragment derived from a full length cDNA clone of genomic segment 9 of bovine rotavirus (NCDV strain) was inserted into Escherichia coli expression plasmid pEX1. The fragment encodes amino acids 50 to 265 of the major vital neutralization antigen VP7, a 326 amino acid long outer shell glycoprotein. Several transformed bacterial clones were isolated in which the recombinant plasmid directed the synthesis of a cro-beta-galactosidase-VP7 fusion protein that was recognized by rabbit polyclonal antibodies against NCDV rotavirus. Sera from rabbits immunized with the fusion protein specifically reacted with VP7 among NCDV virion polypeptides. The chimeric polypeptide was also specifically recognized by two monoclonal antibodies against UK strain rotavirus VP7 that exhibited virus-neutralizing activity. However, immune sera to the chimeric polypeptide showed no neutralizing activity against bovine rotavirus. These results are discussed in view of a recent report that a fusion VP7-beta-galactosidase polypeptide comprising 35 more amino acids at the carboxy terminus was able to induce neutralizing antibodies in mice to simian rotavirus SA11.
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PMID:Expression of bovine rotavirus neutralization antigen in Escherichia coli. 282 74


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