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)

Tetrathionate reduction can be detected simply by acid production. Some commonly occuring Salmonella serotypes can be subdivided into biotypes by the tetrathionate reductase test. The enzyme beta-glucuronidase can be detected using p-nitro-phenyl-beta-D-glucuronide as substrate. The enzyme was found in 30% of Salmonella strains. Each Salmonella serotype was found homogeneous with respect to presence of (or lack of) beta-glucuronidase. This test can then be useful for the identification of monophasic or non-motile variants of normally diphasic serotypes. A positive ONPG-test does not always indicate the presence of a true beta-galactosidase. In the genus Salmonella, ONPG-positive strains of sub-genus III and strains harboring a lactose-plasmid have a true beta-galactosidase. A late positive ONPG-test - as commonly shown by subgenus II strains - is not due to a true beta-galactosidase. The distinction between beta-galactosidase positive and beta-galactosidase negative strains among ONPG-positive strains may be taxonomically significant.
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PMID:[Tetrathionate reductase, beta-glucuronidase, and ONPG-test in the genus Salmonella (author's transl)]. 45 69

Two sisters are described with demonstrable splenomegaly already from infancy and, after the age of 2--4 years, signs of slowly progressive encephalophy, vacuolated lymphocytes in the peripheral blood, and peculiar foam cells in the bone marrow aspirates. The died at 7 3/4 and 6 1/2 years. Widely spread in the brain, the nerve cell bodies were found to show extensive ballooning. It was most striking in the brain stem and spinal cord, while cerebellar structures were remarkably well preserved. The cytoplasm of the ballooned nerve cells was filled with finely granular storage material stainable as a readily soluble glycolipid. The spleen, liver and intestinal wall contained numerous foamy PAS-positive macrophages. Chemical assays showed a ten-fold increase of lactosylceramide and a modest one of minor gangliosides brain cortex. No accumulation sphingomyelin could be revealed, and the sphingomyelinase activity was found to be normal. The ganglioside GM1 beta-galactosidase activity of leucocytes was reduced to 20--25% of normal, which indicated a disturbance of the glycosaminoglycan metabolism. The tissue content of glycosaminoglycans was, however, normal, but an accumulation of lactose was demonstrated in the spleen. It is postulated that the primary enzymic defect is a disturbance of a lysosomal beta-galactosidase with a substrate specificity for lactose and other oligosaccharides with a terminal beta-galactosidic linkage.
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PMID:Neurovisceral storage disorder simulating Niemann-Pick disease. A new form of oligosaccharidosis? 58 Mar 8

Differential diagnosis of enterobacteria is based on the determination of beta-galactosidase enzyme, hydrolyzing lactose in the nutrient substrates; however, the tests suggested for its determination are time consuming and their use in practice is limited. Dry nutrient medium prepared by the authors containing o-nitrophenyl-betaD-pyranoside was tested on 1625 strains of enterobacteria in comparison with the Le Minor's ONPS test used at present. The results of beta-galactosidase determination by the, mentioned methods proved to coincide (significance level greater than 95%); this permits to recommend the method described--in dry nutrient medium--as a differential-diagnostic test for the identification of enterobacteria.
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PMID:[Dry medium for determining the beta-galactosidase activity of enterobacteria]. 59 13

Complex carbohydrates on the surfaces of eukaryotic cells are thought to participate in a wide variety of cell-cell interactions. A model system has therefore been developed to study these processes. In the present experiments, the ability of chicken hepatocytes to recognize and adhere to sugars covalently linked to polyacrylamide gels was investigated. The gels were snythesized by two methods. Type I gels were prepared from a co-polymer of an active ester of acrylic acid (N-succinimidyl acrylate), acrylamide, and bisacrylamide. The "activated" polyacrylamide gel was then treated with the desired ligand containing an amino group, such as 6-aminohexyl O- or S-glycoside. Type II gels were formed by treating similar ligands with acryloyl chloride, followed by co-polymerization of the resulting N-substituted acrylamide with acrylamide and N,N'-methylenebisacrylamide. These polyacrylamide derivatives offer many advantages for studies with intact cells. They are not toxic to any cell type studied, can be cast in any desired shape, are transparent and stable over a wide range of pH values, and contain no cationic and low to negligible levels of anionic charge (charged groups can be introduced if desired), and the polyacrylamide matrix is stable to common biological agents such as bacteria and enzymes. In addition, type I gels can be synthesized using a broad range of molecules containing amino groups, such as glycopeptides, proteins, etc. The hepatocytes were prepared by collagenase perfusion of intact chicken livers. The rate and extent of adhesion of the cells to the derivatized gels was determined by measuring lactate dehydrogenase in these cells. This enzyme was also used to assay viability and cell "leakiness." At 37 degrees C, 70 to 100% of the cells adhered within 60 min to gels derivatized with N-acetylglucosamine, i.e. gels derivatized with 6-aminohexyl 2-acetamido-2-deoxy-beta-D-glucopyranoside (or the corresponding thioglycoside). By contrast, less than 5% of the cells adhered to polyacrylamide or to gels derivatized with 6-aminohexanol or the 6-aminohexyl glycosides of beta-D-glucose, beta-D-galactose, alpha-D-mannose, beta-D-maltose, beta-D-melibiose, beta-D-cellobiose, and (alpha or beta)-D-lactose. Kinetic studies with the chicken hepatocytes and N-acetylglucosamine gels showed that cell-gel binding was dependent upon Ca2+ and was decreased at low temperatures. Binding was inhibited by N-acetylglucosamine or by glycosides of this sugar, the most effective inhibitor being orosomucoid (alpha1-acid glycoprotein) pretreated with sialidase and beta-galactosidase. The cell surface receptor(s) involved in this interaction is not known, but may be related or identical to the chicken liver binding protein described by Lunney and Ashwell (Lunney, J., and Ashwell, G. (1976) Proc. Natl. Acad. Sci. U. S. A. 73, 341--343). The present results suggest that this model system should prove useful in delineating cell surface interactions with carbohydrates.
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PMID:Adhesion of chicken hepatocytes to polyacrylamide gels derivatized with N-acetylglucosamine. 70 Dec 94

A number of plasmids carrying the lactose character have been studied. All of the plasmids examined so far code for proteins essential for lactose utilization, i.e., beta-galactosidase and galactoside permease. None of them carries enzymatically or immunologically detectable thiogalactoside transacetylase. The expression of the two enzymes is both negatively and positively controlled: they are inducible by different galactosides and are sensitive to catabolite repression. Since the plasmid-coded lactose systems have many features in common with the Escherichia coli lactose operon, it is suggested that the plasmids could have acquired the lactose genes from an E. coli chromosome.
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PMID:Expression and regulation of lactose genes carried by plasmids. 78 15

The molecular genetics of GM1 beta-galactosidase is reviewed. This enzyme exists in two forms, A and B. Form A is monomeric with a molecular weight of 72,000 and appears to be coded by a single autosomal locus. Form B is polymeric and cross-reacts with anti-A antibodies; it is coded wholly or in part by the same locus that codes for A. The simultaneous loss of A and B in GM1 gangliosidosis is explained. None of the other beta-galactosidases, including neutral beta-galactosidase, ceramide lactoside beta-galactosidase or cerebroside beta-galactosidase cross-react with anti-A antibodies, demonstrating that they are coded by loci separate from A. GM1 beta-galactosidase A is heterocatalytic, cleaving beta-D-galactose from ganglioside GM1, lactose, N-acetyllactosamine, and galactose-containing glycoproteins such as asialofetuin, red cell stromal glycoproteins and keratan sulfate. The pleotropic effects of a single mutation affecting the locus for beta-galactosidase A can be explained by a one gene:one polypeptide:many substrates model. Phenotypic variability among beta-galactosidase A mutants may result from better residual activity of the mutant enzyme for one substrate than for another. Patients with normal intelligence and severe bony deformities, who are homozygous for a mutation affecting the enzyme, illustrate this point. Thus far all human mutants for GM1 beta-galactosidase studied are structural mutants, synthesizing nearly normal quantities of mutant enzyme; one is a proven Km mutant, the others are very likely so.
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PMID:Molecular genetics of GM1 beta-galactosidase. 81 20

Beta-Galactosidase (beta-D-galactoside galactohydrolase 3.2.1.23) from Curvularia inaequalis was immobilized by glutaric dialdehyde on gamma-aminopropyl triethoxysilane treated porous siliceous carrier silochrome. From the crude preparation with a specific activity of 3.1 U/mg immobilized beta-galactosidase with an activity of 113 U/g was obtained. The immobilized enzyme did not show significant changes in its enzymic properties. The column filled with the resultant preparation and used to hydrolyze lactose in milk whey maintained 50% of its initial activity after a 30-day work at 50 degrees C.
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PMID:[Immobolization of beta-galactosidase on silochrome]. 103 46

Lactase (beta-galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o-nitrophenyl-beta-D-galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion-free and completely diffusion-controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.
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PMID:Hydrolysis of D-galactosides in an open tubular lactase reactor. 104 83

Highly purfied beta-galactosidase from fungus Curvularia inaequalis cultural fluid with a specific activity of 50 units per mg of protein was obtained by 2-fold purification of the enzyme, using chromatography on DEAE-cellulose and on hydroxylapatite. The enzyme was found to hydrolyze o-nitrophenyl-beta-D-galactopyranoside (pH optimum of 3.7--4.5) and lactose (pH optimum 3.9--5.3). The isoelectric point was observed at pH 4.4 the temperature optimum was 60 degrees C. The molecular weight (115 000--126 000) and the amino acid composition of the enzyme were determined. Km values for o-nitrophenyl-beta-D-galactopyranoside and lactose were 0.55-10(-3) M and 4.5-10(-3) M respectively. Disc-electrophoresis in polyacrylamide gel revealed a single band with a specific activity. The homogeneity of the enzyme was found in ultracentrifuge.
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PMID:[Purification and properties of beta-galactosidase from fungus, Curvularia inaequalis]. 105 94

We have constructed a plasmid cloning vehicle in which transcription of inserted heterologous DNA fragments can be regulated by a defined bacterial operator and promoter. The lambda plac 5 EcoRIDNA fragment containing the operator, promoter, and beta-galactosidase gene of the lactose operon was linked to the ColE1 derivative plasmid pSF2124, creating a plasmid designated pBGP100, pBGP100 contains one EcoRI site at the lac DNA/pSF2124 DNA junction and another at the lambda DAN/pSF2124 DNA junction. We deleted the latter EcoRI site to generate a plasmid (pBGP120) retaining a single EcoRI site at the lac DNA/nSF2124 DNA junction. To determine whether DNA introduced at the EcoRI site of pBGP120 was expressed under lactose control, we inserted the EcoRI fragment containing 28S ribosomal DNA of Xenopus laevis, creating the hybrid plasmid pBGP123. RNA-DNA hybridization of pulse-labeled RNA from cells containing pBGP123 showed that induction of the lac operon increases the percentage of labeled RNA complementary to Xenopus 28S DNA about 9-fold. This vehicle may be of use for production of eukaryotic gene products in bacteria.
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PMID:A plasmid cloning vehicle allowing regulated expression of eukaryotic DNA in bacteria. 106 75


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