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)

Derivatives of Drosophila 70,000 dalton heat shock protein (hsp70) genes were constructed in which all of the hsp70 coding sequence but for the first seven codons had been substituted by a DNA segment coding for E. coli beta-galactosidase. The constructs were capable of directing the synthesis of active beta-galactosidase in COS1 (SV40 transformed African Green Monkey Kidney) cells. The hybrid genes were then used to develop a procedure permitting the introduction of genes and their transient expression in cultured cells of Drosophila melanogaster. Introduction of hybrid genes was achieved by DEAE-dextran-mediated transfection. Substantial gene activity was observed in heat-treated cells only 4 h, maximal activity 24 h after transfection. Various parameters of the transfection/transient expression system including the effects of different 3'nontranslated sequences on hybrid gene expression were investigated in an attempt to provide a useful procedure for studies of the expression of other genes in D. melanogaster cells. To show that promoters which are weaker than that of the hsp70 gene direct the synthesis of easily measurable amounts of beta-galactosidase in D. melanogaster cells, the expression of a hsp84-beta-galactosidase hybrid gene was also examined. Expression of the hsp70 hybrid gene occurs during heat shock, at temperatures at which other proteins are not made, and decreases sharply after heat treatment. The expression of the transfected gene therefore closely follows that of the endogenous hsp70 genes. This result suggests that a short hsp70 gene segment consisting of 195 base pairs of upstream sequence and a complete RNA leader region contain all the information required for the induced synthesis of proteins during heat shock.
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PMID:Expression of heat shock-beta-galactosidase hybrid genes in cultured Drosophila cells. 644 Nov 1

In search of a beta-galactosidase which specifically hydrolyses beta 1----3 bound galactose residues in galacto-glycoconjugates, an acid beta-galactosidase from chicken liver was investigated. The isolation procedure involved ammonium sulphate precipitation followed by lectin chromatography on Con A-Sepharose 4B, ion-exchange chromatography on DEAE-cellulose, gel filtration on Sepharose 6B and affinity chromatography on p-aminophenyl-thio-beta-D-galactoside-agarose. The beta-galactosidase was purified 3000-fold with 11% recovery of enzyme activity. The purified protein showed an apparent molecular mass of above 200000 in SDS-polyacrylamide gel electrophoresis. A few minor bands were also present. The reduced and denatured beta-galactosidase migrated as a single major band with an apparent molecular mass of 67000. The enzyme released galactose from lactose and from the synthetic substrates Gal beta 1----3Gal, Gal beta 1----6Gal and Gal beta 1----3Ara. However, the enzyme did not release galactose from the snail gland galactans and the high molecular weight galacto-glycoconjugates and it did not hydrolyse the peanut agglutinin receptor of the red blood cell membrane.
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PMID:Isolation of a beta-galactosidase from chicken liver. 644 30

The complex between lactase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) and phlorizin hydrolase (glycosyl-N-acylsphingosine glycohydrolase, EC 3.2.1.62) has been purified from the proximal and distal regions of the small intestine of suckling rats. The two enzymes behaved differently on DEAE-cellulose ion-exchange chromatography and during electrophoresis in the presence and absence of sodium dodecyl sulphate (SDS), but they have very similar cyanoge bromide cleavage patterns. Kinetic studies on the proximal and distal enzymes showed the same pH optimum of 6.0 and the same heat stability at 45 degrees C, but a small difference in Km. Treatment of both enzymes with fucosidase, mannosidase or N-acetylhexosaminidase did not affect enzymic activity or electrophoretic mobility. Neuraminidase digestion abolished the electrophoretic differences and gave two active enzymes with similar isoelectric points.
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PMID:Isolation and characterization of the proximal and distal forms of lactase-phlorizin hydrolase from the small intestine of the suckling rat. 677 1

A new procedure for inducing and purifying endo-beta-galactosidase from Escherichia freundii was described. The enzyme was found to be induced with high efficiency in culture medium containing Smith-degraded hog gastric mucin, which was prepared from a commercially available starting material. Endo-beta-galactosidase was then purified by ammonium sulfate fractionation, DEAE-Sephadex chromatography, and affinity chromatography on Sepharose conjugated with the Smith-degraded mucin. The enzyme thus purified by only three steps showed no other glycosidase or protease activities and had higher specific activity compared to the previous method. This new method has a great advantage since the gastric mucin is abundantly available and the efficiency of enzyme production was high without significant induction of exoglycosidase. The hydrolysis of oligosaccharides, glycosphingolipid, and keratansulfate was studied by using this newly purified enzyme. Kinetic data indicate that hydrolyzability of these substrates is largely affected by substrate concentration, enzyme concentration and the structure of substrates. Based on these results, the specificity of E. freundii endo-beta-galactosidase was discussed.
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PMID:Purification and characterization of endo-beta-galactosidase from Escherichia freundii induced by hog gastric mucin. 678 49

beta-Galactosidase from Alternaria tenius was purified to homogeneity from the cultural fluid using acetone precipitation, ion-exchange chromatography on DEAE-cellulose, adsorption on hydroxylapatite and affinity chromatography on N-(beta-D-galactopyranosyl-thiocarbamoyl)-beta-aminocaproyl-AN-Sepharose 4B. The enzyme homogeneity was demonstrated by ultracentrifugation and polyacrylamide gel electrophoresis with SDS or without it. The specific activity of the homogeneous enzyme is 160 u. per mg of protein; mol. weight as determined by various methods is 142 000-176 000, pI = 4.6, temperature optimum is 60-65 degrees, pH optima for o-nitrophenyl-beta-D-galactopyranoside (o-NPG) and lactose are 3.8--4.4 and 3.6--4.8, respectively. The Km values for o-NPG and lactose are 0.21 . 10(-3) and 6.57 . 10-3 M, respectively. The enzyme is a glycoprotein and contains up to 30% of carbohydrates. EDTA and pCMB have no effect on the beta-galactosidase activity. Galactose acts as a competitive inhibitor, while glucose has no inhibiting effect on the enzyme activity.
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PMID:[Purification and properties of beta-galactosidase from Alternaria tenius]. 679 53

Band-3 glycoprotein was purified from human blood-group-A erythrocyte membranes by selective solubilization and gel chromatography on Sepharose 6B in the presence of sodium dodecyl sulphate. The purified glycoprotein was subjected to hydrazinolysis in order to release the carbohydrate moiety. The released oligosaccharides were N-acetylated and applied to a column of DEAE-cellulose. Most of the band-3 oligosaccharides obtained were found to be free of sialic acids. When this neutral fraction was subjected to gel chromatography on a column of Sephadex G-50, two broad peaks were observed indicating that the band-3 glycoprotein was heterogeneous in the size of the oligosaccharide moieties. All fractions from gel chromatography were found to contain galactose, mannose, N-acetylglucosamine and fucose. The higher-molecular-weight (mol.wt. 3000-8000) peak consisted of fucose, mannose, galactose, N-acetylglucosamine and N-acetylgalactosamine in a molar proportion of 1.6:3.0:8.4:10.5:0.2. Most of these oligosaccharides were digested with a mixture of beta-galactosidase and beta-N-acetylhexosaminidase after alpha-L-fucosidase treatment to give a small oligosaccharide with the structure alpha Man2-beta Man-beta GlcNAc-GlcNAc. Methylation studies and limited degradation by nitrous acid deamination showed that the oligosaccharides contained the repeating disaccharide Gal beta 1----4GlcNAc beta 1----3, with branching points at C-6 of some of the galactose residues. These results indicate that a major portion of the band-3 oligosaccharide has a common core structure, with heterogeneity in the numbers of the repeating disaccharides, and contains fucose residues both in the peripheral portion and in the core portion. Haemagglutination tests were also carried out to determine the blood-group specificities of the glycoprotein and the results demonstrated the presence of both blood-group-H and I antigenic activities.
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PMID:The carbohydrate moiety of band-3 glycoprotein of human erythrocyte membranes. 718 22

Neuraminidase (acylneuraminyl hydrolase, EC 3.2.1.18) from the influenza virus A/Hong Kong/68 (H3N2) was purified after treatment of the purified virus with sarcosyl (sodium laurylsarcosinate), centrifugation at 110 000 x g, and chromatography on DEAE-Sephadex and Sephadex G-200. It migrated as a single component during electrophoresis on polyacrylamide gel, and its molecular weight was estimated about 270 000. The enzyme was thermolabile, the activity being reduced to 60% in 10 min at 50 degrees C. The purified neuraminidase had an apparent Km value of 4.1 . 10(-3) M for 5-N-acetyl-2-O-(3-methoxyphenyl)-alpha-D-neuraminic acid and was able to release sialic acid with linkages alpha 2-3, alpha 2-6 and alpha 2-8 (with very different efficiency) from fetuin, gangliosides, colominic acid, and bovine and porcine submaxillary mucins. The enzymic activity was measured by several procedures: (A) spectrophotometric determination at 340 nm of the NADH produced in the reaction catalysed by beta-galactose dehydrogenase on beta-galactose + NAD+, this beta-galactose was the product released from lactose by beta-galactosidase and lactose was the product of the neuraminidase activity on N-acetylneuraminyl-lactose; (B) determination of the colored quinone yielded by the liberated methoxyphenol with 4-aminoantipyrine (Santer, U.V., Yee-Foon, J. and Glick, M.C. (1978) Biochim. Biophys. Acta 523, 435-442); (C) periodate-thiobarbiturate procedures (Warren, L. (1959) J. Biol. Chem 234, 1971-1975 or Aminoff, D. (1961) Biochem. J. 81, 384-391). Some peculiarities of these methods are discussed.
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PMID:Neuraminidase from influenza virus A (H3N2): specificity towards several substrates and procedure of activity determination. 721 37

Two forms of alkaline phosphatase (orthophosphoric monoester phosphohydrolase (alkaline optimum, EC 3.1.3.1) have been purified from human small intestine by column chromatography on DEAE-cellulose and tyraminyl derivative affinity gel, and by preparative disc gel electrophoresis. Intestinal phosphatases were electrophoretically separated into two components, fast- and slow-moving enzymes, with apparent molecular weights of 140000 and 168000 and with subunit weights of 68000 and 80000, respectively. Analyses of carbohydrate and amino acid revealed marked differences in the two enzymes. Enzymatic properties and affinities for an anti-blood group antibody were also found to differ. Papain digestion released a hydrophobic small peptide from the slow-moving enzyme and its enzymatic properties resembled those of the fast-moving enzyme. Circulating clearance (T1/2) of the slow- and fast-moving enzymes from adult intestine was found to be 7.5 h and 1.3 h, respectively; that of fetal intestinal enzyme was 2.8 h. Sialidase, sialidase/beta-galactosidase, or sialidase/beta-galactosidase/N-acetyl-beta-glucosaminidase treatment of the fetal enzyme reduced the value to about 40 min. Further, digestion with alpha-fucosidase, alpha-mannosidase or both restored it to nearly the original level. Organ distribution of injected 125I-labelled enzymes indicates that the desialylated hepatic enzyme was selectively distributed in liver, while the degalactosylated intestinal enzyme was incorporated into liver lymph fluid, and small intestine. These results suggest that the pathway of circulating clearance of alkaline phosphatase has several routes.
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PMID:Multiple forms of human intestinal alkaline phosphatase: chemical and enzymatic properties, and circulating clearances of the fast- and slow-moving enzymes. 730 75

The activity of acid phosphatase (E.C.3.1.3.2.), arylsulfatase (E.C.3.1.1.23.), beta-galactosidase (E.C.3.1.1.23.), and beta-acetylglucosaminidase (E.C.3.2.1.30.) in rat liver homogenates of 4.5 month-old male rats is presented in this paper. The degradation processes are observed in rat liver homogenate after incubation. The activity of acid phosphatase and beta-acetylglucosaminidase increases, the activity in one of beta-galactosidase is constant, and arylsulfatase decreases during the time of incubation. Furthermore, the maxima of the enzyme activities shift during the incubation in the time of a day. Gel filtration of acid phosphatase on the Sephadex G-150 Superfine and DEAE-cellulose columns determinate the mutual content of acid phosphatase subunits to isoenzymes I and II in various points of a day. The greatest content of acid phosphatase subunits versus both the isoenzymes content is at 02(24), and the greatest content of isoenzyme II versus the content of isoenzymes I appears at 07(12). From these data it is clear that the period of the isoenzyme II synthesis from the subunit amounts to 5 h, while 10 h are necessary to create the isoenzyme I originated from isoenzyme II. The comparison of acid phosphatase activity before and after the homogenate filtration on the Sephadex column indicates the increase of this enzyme activity after its separation from the other proteins and other components.
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PMID:Rhythmic changes of some lysosomal hydrolases activity from rat liver. Rhythmic changes of acid phosphatase synthesis. 730 16

The fruit extracts of ripening cv. Harumanis mango contained a number of glycosidases and glycanases. Among the glycosidases, beta-D-galactosidase (EC 3.2.1.23) appeared to be the most significant. The enzyme activity increased in parallel with increase in tissue softness during ripening. Mango beta-galactosidase was fractionated into three isoforms, viz. beta-galactosidase I, II and III by a combination of chromatographic procedures on DEAE-Sepharose CL-6B, CM-Sepharose and Sephacryl S-200 columns. Apparent Km values for the respective beta-galactosidase isoforms for p-nitrophenyl beta-D-galactoside were 3.7, 3.3 and 2.7 mM, and their Vmax values were 209, 1024 and 62 nkat mg-1 protein. Optimum activity occurred at ca pH 3.2 for beta-galactosidase I and II, and pH 3.6 for beta-galactosidase III. Mango beta-galactosidase and its isoforms have galactanase activity, and the activity of the latter in the crude extracts generally increased during ripening. The close correlation between changes in beta-galactosidase activity, tissue softness, and increased pectin solubility and degradation suggests that beta-galactosidase might play an important role in cell wall pectin modification and softening of mango fruit during ripening.
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PMID:beta-Galactosidase and its significance in ripening mango fruit. 776 93


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