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)

The ugp promoter (pugp) responsible for expression of the binding-protein-dependent sn-glycerol-3-phosphate transport system in Escherichia coli was cloned into a small multicopy plasmid pTER5, a derivative of pBR322, between the transcription terminators rpoCt and tL1. The resulting expression vector, pPH3, permits convenient insertion of structural genes containing their own translational-initiation regions, into the multiple-cloning site derived from the pUC19 plasmid. The efficiency and regulatory properties of pugp were measured using xylE and lacZ as reporter genes, which code for the corresponding enzymes catechol-2,3-dioxygenase (C23O) and beta-galactosidase (beta Gal), respectively. Enzyme activities were virtually completely repressed in the presence of excess inorganic phosphates (Pi) and high concentrations of glucose. Maximal induction was observed at limiting Pi (less than 0.1 mM) and normal levels of glucose (0.2-0.4%). The maximum expression of the pugp-directed beta Gal synthesis was approx. 80% of that directed by strong ptac. When the xylE gene was maximally expressed, the induced enzyme constituted approx. 50% of total cellular protein as judged by laser densitometry following sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. These results suggest the usefulness of the pugp in expression vectors for strong, but controlled, expression of cloned genes in E. coli. This Pi controlled vector can be adapted to large-scale fermentation by using Pi-limiting growth conditions.
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PMID:A novel phosphate-regulated expression vector in Escherichia coli. 237 33

Flavonoids (103 species) were tested for inhibitory activity against influenza virus sialidase using sodium p-nitrophenyl-N-acetyl-alpha-D-neuraminate as substrate. 5,7,4'-Trihydroxy-8-methoxyflavone from the root of Scutellaria baicalensis showed the most potent activity (IC50, 55 microM), and this flavone appeared to be a non-competitive inhibitor of the enzyme. Whereas, negligible or weak inhibitory activities were observed for mouse liver sialidase, beta-galactosidase and alpha-mannosidase as tested. This flavone also inhibited the infection by influenza virus A/PR/8/34 of Madin-Darby canine kidney cells, and replication of the virus in the allantoic sack of embryonated egg. These results suggest that flavone, which has potent influenza virus sialidase inhibitory activity, may have anti-influenza virus activity.
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PMID:Inhibition of influenza virus sialidase and anti-influenza virus activity by plant flavonoids. 239 58

Fischer rat protective antiserum (F-2x) prepared from Schistosoma mansoni-infected rats was used to screen an adult worm cDNA library constructed in a lambda gt11 bacteriophage expression vector. This led to the isolation of several clones yielding proteins reactive with antibodies in the infection serum. Counter-screening of these clones with Wistar-Furth rat nonprotective antiserum (W-2x) enabled identification of clones either uniquely or preferentially reacting with F-2x, in addition to clones of nearly equal reactivity with both antisera. Six clones were further characterized. Five expressed beta-galactosidase/S. mansoni fusion proteins which migrated more slowly in sodium dodecyl sulfate-polyacrylamide gel electrophoresis than beta-galactosidase and all were reactive in a Western immunoblot assay. The cDNA insert sizes in the clones ranged from 150 to 900 base pairs. Rabbit antibodies prepared against fusion proteins from three of the clones recognized biosynthetically radio-labeled 4-week worm proteins of sizes 20, 38, and 70 kDa, respectively. The 20- and 38-kDa proteins were among the protein antigens uniquely recognized by the F-2x protective antiserum. These proteins are therefore candidates for protective vaccine antigens and the recombinant lambda clones are now serving as useful reagents for obtaining the corresponding nucleotide gene sequences.
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PMID:Schistosoma mansoni: cloning of antigen gene sequences in Escherichia coli. 240 33

In the cell adhesion of aggregation-competent Dictyostelium cells, the requirement for the carbohydrate moiety of the glycoprotein appeared to be indirect in that it acts to protect the protein moiety from proteolytic degradation; however, the effect was limited to the tunicamycin (TM)-sensitive carbohydrate moiety (Hirano, T., et al. (1983) J. Biochem. 93, 1249-1257). In the present study, we showed that the EDTA-stable adhesion of aggregation-competent Dictyostelium cells was abolished by the treatment of intact cells with jack bean alpha-mannosidase, whereas neuraminidase, beta-galactosidase, beta-N-acetylhexosaminidase, or alpha-L-fucosidase had no effect. The EDTA-stable cohesiveness of TM-treated cells in the presence of leupeptin (TM/LP cells) was also abolished by the treatment of the cells with alpha-mannosidase. The effect of alpha-mannosidase was not prevented in the presence of LP. The N-glycoside-deficient contact site A (an adhesion-mediating glycoprotein) was obtained from TM/LP cells and was shown to have a molecular weight of 70,000. This protein (p 70) was shown to still have carbohydrates as detected by polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS) and subsequent staining of the gel with periodic acid-silver stain. Moreover, p 70 reacted with anti-gp 68, which has a specificity against alpha-mannosyl residues of carbohydrate chains. However, p 70 treated with alpha-mannosidase showed decreased reactivity with anti-gp 68. The monovalent antibody fragment of anti-contact site A or anti-p 70 inhibited EDTA-stable cell adhesion of both control and TM/LP cells. These results indicated that TM-resistant mannosyl residues of contact site A are directly involved in EDTA-stable adhesion of aggregation-competent cells. This is the first report of the direct involvement of the carbohydrate moiety in cell adhesion of aggregation-competent Dictyostelium cells. A schematic model is presented of the role of the carbohydrate moiety in EDTA-stable cell adhesion, including the direct effect of carbohydrates.
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PMID:Direct implication of surface mannosyl residues in cell adhesion of Dictyostelium discoideum. 241 9

Monoclonal antibodies specific for the 'latent membrane protein' (LMP) of Epstein-Barr virus (EBV), one of the effector proteins of EBV-induced B cell transformation, have been generated from mice immunized with a beta-galactosidase fusion protein containing the carboxyl half of the B95.8 strain LMP sequence. Four monoclonal IgG1 antibodies, designated CS.1, CS.2, CS.3 and CS.4, which together recognized at least three different epitopes on the molecule, were used to examine various aspects of LMP expression in B cell lines transformed in vitro. The pooled CS.1 to 4 reagent detected the LMPs encoded by each of 20 geographically distinct EBV isolates, despite a degree of inter-isolate heterogeneity in the size and antigenicity of the protein. In cell lines carrying the prototype B95.8 virus strain, particularly if these were virus producers, an additional lower molecular weight LMP was also detected; this appeared to correspond to the truncated form of the protein already predicted to exist from the analysis of B95.8 lytic cycle mRNAs. Attempts were made to identify an analogous truncated form of LMP in cell lines carrying other virus isolates after treatment with phorbol ester and/or sodium butyrate to induce virus production. Surprisingly these experiments showed that expression of the full length LMP molecule was itself strongly inducible by these agents; when monitored at the single cell level, this was a generalized response and was not restricted to cells entering a lytic cycle. Expression of LMP in EBV-transformed B cells therefore appears to be subject to a distinct type of regulation.
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PMID:Monoclonal antibodies to the latent membrane protein of Epstein-Barr virus reveal heterogeneity of the protein and inducible expression in virus-transformed cells. 243 76

The chondroitin sulfate proteoglycans of brain contain several core proteins bearing HNK-1 antibody epitopes. Endo-beta-galactosidase treatment resulted in the almost complete disappearance of HNK-1 staining of proteoglycan immunoblots, indicating that a significant portion of the 3-sulfated sugar residues recognized by this antibody are present on poly(N-acetyllactosaminyl) oligosaccharides. However, after treatment with chondroitinase ABC followed by endo-beta-galactosidase, several proteoglycan species showed HNK-1 reactivity, presumably due to the presence of this epitope on other oligosaccharides which are both resistant to endo-beta-galactosidase and inaccessible to the antibody in the native proteoglycan. Immunostaining of the endo-beta-galactosidase degradation products after separation by thin-layer chromatography demonstrated that HNK-1 reactivity was confined to a minor population of large oligosaccharides. Only a relatively small portion of the native chondroitin sulfate proteoglycans of brain enter a 6-12% SDS-polyacrylamide gel. However, after treatment of the proteoglycans with chondroitinase ABC (or chondroitinase and endo-beta-galactosidase) in the presence of protease inhibitors, seven bands with molecular sizes ranging from 80 to 200 kDa appear in Coomassie Blue stained gels, and two additional bands with molecular sizes of 67 and 350-400 kDa are apparent in fluorographs of sodium [35S]sulfate labeled proteoglycans. Most of these components probably represent individual proteoglycan species rather than different degrees of nonchondroitin sulfate/keratan sulfate glycosylation of a single protein core, since [35S]methionine-labeled proteins of comparable molecular size were synthesized by an in vitro translation system. These findings suggest that chondroitin sulfate proteoglycans which differ in molecular size and composition may be specific to particular cell types in brain.
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PMID:Presence of the HNK-1 epitope on poly(N-acetyllactosaminyl) oligosaccharides and identification of multiple core proteins in the chondroitin sulfate proteoglycans of brain. 247 68

Daily s.c. injection of gentamicin at either 100 mg/kg for 4 days or 60 mg/kg for 2 weeks produced nephrotoxicity in the adult rat as judged by an increase in urinary excretion of beta-galactosidase, beta-glucuronidase and beta-N-acetylglucosaminidase. The observed enzymuria was associated with significant elevation in total renal phospholipid, phosphatidylinositol, phosphatidylcholine and phosphatidylserine. In addition, gentamicin decreased the activities of renal cortical Na+-K+-adenosine triphosphatase, alkaline phosphatase as well as phospholipase C. Pyridoxal-5'-phosphate (250 mg/kg/day) administered i.p. for 4 or 14 days did not markedly alter the metabolic markers of kidney function. In rats simultaneously given pyridoxal-5'-phosphate and gentamicin for 4 days the vitamin failed to prevent either the antibiotic-induced decrease in renal phospholipase C and alkaline phosphatase or the increase in total renal phospholipid, phosphatidylinositol, phosphatidylcholine and phosphatidylserine. However, simultaneous pyridoxal-5'-phosphate and aminoglycoside treatment for 2 weeks proved effective in blockade of the gentamicin-induced kidney phospholipidosis, elevation in urinary beta-galactosidase, beta-glucuronidase and beta-N-acetylglucosaminidase, as well as reduction in renal phospholipase C and alkaline phosphatase. The gentamicin-induced nephrotoxicity was associated with a decrease in renal pyridoxal-5'-phosphate levels. In the simultaneous 4-day-treated rat the renal concentration of pyridoxal-5'-phosphate returned to approximate control values, whereas after 2 weeks the level of vitamin B6 was approximately 2-fold higher than control. Although pyridoxal-5'-phosphate in the simultaneous group lowered kidney gentamicin content by 40% after 4 or 14 days, protection from aminoglycoside-induced nephrotoxicity was apparent only after 2 weeks in our study.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of gentamicin-induced nephrotoxicity by pyridoxal-5'-phosphate in the rat. 249 42

One of the final steps in epidermal differentiation is the conversion of glucosylceramides to ceramides, which presumably is mediated by a beta-glucosidase activity. In the present manuscript, it is demonstrated that pig epidermis contains beta-glucosidase activity which is 3.3-times greater than alpha-glucosidase and 5-times greater than beta-galactosidase. This beta-glucosidase was found to be maximally active between pH 3.0 and essentially inactive at pH 9.0. In a standard assay, a disk of epidermis (8 mg dry weight) was submerged in 1 ml of 50 mM acetate buffer (pH 4.7) containing 150 mM NaCl and 15 mM p-nitrophenyl-beta-D-glucopyranoside at room temperature. Reaction was stopped by addition of 4 ml of 100 mM (pH 9.0) borate buffer and the supernatant was transferred to a separate tube. The nitrophenylate anion was then measured spectrophotometrically at a wavelength of 405 nm. Under these conditions, product formation was linear for at least 90 min and an apparent Km of 244 microM was estimated for the synthetic substrate. When the amount of epidermis in the assay was varied, the formation of product per unit of time remained proportional to the amount of epidermis. The level of beta-glucosidase activity was enhanced slightly by the inclusion of sodium taurocholate.
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PMID:Beta-glucosidase activity in porcine epidermis. 249 22

The thermodynamics of the hydrolysis of lactose to glucose and galactose have been investigated using both high pressure liquid chromatography and heat-conduction microcalorimetry. The reaction was carried out over the temperature range 282-316 K and in 0.1 M sodium acetate buffer at a pH of 5.65 using the enzyme beta-galactosidase to catalyze the reaction. For the process lactose(aq) + H2O(liq) = glucose(aq) + galactose(aq), delta G0 = -8.72 +/- 0.20 kJ.mol-1, K0 = 34 +/- 3, delta H0 = 0.44 +/- 0.11 kJ.mol-1, delta S0 = 30.7 +/- 0.8 J.mol-1.K-1, and delta Cop = 9 +/- 20 J.mol-1.K-1 at 298.15 K. The standard state is the hypothetical ideal solution of unit molality. Thermochemical cycle calculations using enthalpies of combustion and solution, entropies, solubilities, activity coefficients, and apparent molar heat capacities have also been performed. These calculations indicate large discrepancies which are attributable primarily to errors in literature data on the enthalpies of combustion and/or third law entropies of the crystalline forms of the substrates.
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PMID:A calorimetric and equilibrium investigation of the hydrolysis of lactose. 249 41

The proteins p15 and p24 of the human immunodeficiency virus (HIV) type 1 gag gene were expressed as fusion proteins in Escherichia coli for detecting antibodies against the acquired immunodeficiency virus by Western blot (immunoblot) analysis. These fusion proteins contain amino acids 1 to 375 of the E. coli beta-galactosidase linked to the viral protein(s) by a recognition sequence for the specific protease factor Xa. They are obtained in large amounts in insoluble inclusion bodies. To avoid ambiguous results caused by cross-reaction of sera with bacterial proteins in Western blots, we purified the recombinant fusion proteins and subsequently removed the bacterial part of the fusions by cleavage with factor Xa. The cleavage mixtures were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nitrocellulose membranes. The viral proteins obtained by this method did not contain any bacterial proteins or protein fragments. Thus, false-positive results in HIV Western blot analysis with bacterially expressed HIV proteins can be excluded with these purified recombinant viral antigens.
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PMID:Cleavage of procaryotically expressed human immunodeficiency virus fusion proteins by factor Xa and application in western blot (immunoblot) assays. 250 57


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