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)

1. The p-nitrophenyl beta-D-galactosidase asctivity in rat liver homogenates of lysosome-rich fractions was shown to be markedly affected by the ionic composition of the medium. A stimulation of the reaction rate at pH 5 was produced by most of the salts tested, which contained anions such as acetate, SO4(2-) and Cl-, and cations such as Na+, K= and Mg2+. The most pronounced effect was observed with MgCl2. Only potassium glutamate was inhibitory. 2. Five peaks of beta-galactosidase activity obtained by DEAE-cellulose chromatography were equally sensitive to changes in the ionic composition of the medium. In the presence of added NaC1, the whole rate-pH curve was displaced towards higher pH values, the optimum being shifted from 2.0-2.5 to 3.5. The stimulation at pH 5.0 appeared to be mainly due to changes in Vmax., whereas the apparent Km was slightly modified. 3. Unlike the total, the free beta-galactosidase activity remained unchanged or even declined when KC1 was added to the reaction medium.
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PMID:Stimulation of rat liver beta-galactosidase activity by ions. 0 74

Mutants altered in carbon catabolite regulation have been isolated by selecting for mutants of the areA217 strain capable of using acetamide as the sole nitrogen source in the presence of sucrose. In addition to creA mutants described previously be Arst and Cove, strains with mutations in two new genes, creB and cre C, have been found. The creB and creC mutants grow poorly on some sole carbon sources and have low levels of some enzymes of carbon catabolism e.g. beta-galactosidase and D-quinate dehydrogenase. The creB and creC mutants are hypersensitive to fluoroacetate, fluoroacetamide and allyl alcohol in the presence of glucose or sucrose but not glycerol; and the enzymes, acetamidase and alcohol dehydrogenase, are less sensitive to carbon catabolite repression than the wild-type strain. Extracellular protease and alpha-glucosidase enzyme activities are elevated in creB and creC mutants, while L-proline and L-glutamate uptake capacities are lower in both the presence and absence of glucose. Interactions between creA, B and C mutations have been investigated in double mutants, and the dominance properties of creB and creC mutants determined. The results indicate that the creB and creC genes may have a regulatory role in the control of carbon catabolism.
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PMID:Pleiotropic mutants of Aspergillus nidulans altered in carbon metabolism. 32 Apr 55

This communication describes the isolation and characterization of mutants of Rhizobium trifolii which can induce nitrogenase activity in defined liquid medium. Two procedures were used for the isolation of these mutants from R. trifolii strain DT-6: (1) following chemical mutagenesis, slow growing mutants were selected which were unable to utilize NH+4 as sole source of nitrogen; (2) as spontaneous mutants resistant to the glutamate analogue L-methionine-DL-sulfoximine. Mutants (DT-71, DT-125) isolated by these procedures induced nitrogenase activity in the free-living state, whereas the parent strain lacked this property. Induction of nitrogenase activity in these mutants occurred during the late exponential phase of growth when the rate of protein synthesis was decreasing. The addition of NH+4 to a medium containing glutamate as the nitrogen-source resulted in a 50--70% reduction (repression?) of nitrogenase activity; in contrast, the rate of protein synthesis or the rate of respiration was not influenced by exogenous NH+4. Biochemical analysis showed that these mutants (strains DT-71 and DT-125) have defects in both nitrogen and carbon metabolism. The levels of glutamate synthase (both NADP+ -and NAD+ -dependent activities) and glutamate dehydrogenase (NAD+-dependent activity) were markedly lower. In addition, the mutants were found to have no detectable ribitol dehydrogenase or beta-galactosidase activity. These findings are discussed in relation to a mechanism of regulation of symbiotic nitrogen fixation.
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PMID:Regulation of nitrogen fixation in Rhizobium spp. Isolation of mutants of Rhizobium trifolii which induce nitrogenase activity. 58 92

A mutant of Escherichia coli is described whose cells show a spherical or irregular morphology, associated with leakage of beta-galactosidase and other intracellular proteins. The expression of the morphologic abnormality is most marked when the mutant is grown in rich media and is suppressed by D-alamine, D-serine, D-glutamate, or glycine supplementation. D-Alanine is the most effective amino acid supplement, half maximally supressing this anomalous property at a concentration of 75 mug/ml, as measured by the reduction in beta-galactosidase released from the cells. The mutant is more sensitive to penicillin G, D-methionine, and D-valine and it is relatively resistant to lysozyme. These phenotypic abnormalities are likewise corrected by the above supplementations. The relative rates of peptidoglycan synthesis in mutant and parent, grown under restrictive conditions, were measured both in vivo and in vitro by rates of incorporation of L-[14-D]alanine and uridine-5'-diphosphate-N-acetyl-D-[1-15C-A1-glucosamine, respectively. There is not metabolic block in the biosynthesis of uridine-5'-diphosphate-N-acetyl-muramyl-pentapeptide as shown by enzymic analysis and the lack of accumulation of uridine-5'-diphosphate-N-acetylmuramyl-peptide precursors. These preliminary studies suggest that the mutant possesses a defect in the biosynthesis of peptidoglycan although the exact lesion has not yet been established.
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PMID:D-Alanine-requiring cell wall mutant of Escherichia coli. 109 98

The PRO1 gene of Saccharomyces cerevisiae encodes the 428-amino-acid protein gamma-glutamyl kinase (ATP:L-glutamate 5-phosphotransferase, EC 2.7.2.11), which catalyzes the first step in proline biosynthesis. Amino acid sequence comparison revealed significant homology between the yeast and Escherichia coli gamma-glutamyl kinases throughout their lengths. Four close matches to the consensus sequence for GCN4 protein binding and one close match to the RAP1 protein-binding site were found in the PRO1 upstream region. The response of the PRO1 gene to changes in the growth medium was analyzed by measurement of steady-state mRNA levels and of beta-galactosidase activity encoded by a PRO1-lacZ gene fusion. PRO1 expression was not repressed by exogenous proline and was not induced by the presence of glutamate in the growth medium. Although expression of the PRO1 gene did not change in response to histidine starvation, both steady-state PRO1 mRNA levels and beta-galactosidase activities were elevated in a gcd1 strain and reduced in a gcn4 strain. In addition, a pro1 bradytrophic strain became completely auxotrophic for proline in a gcn4 strain background. These results indicate that PRO1 is regulated by the general amino acid control system.
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PMID:Proline biosynthesis in Saccharomyces cerevisiae: molecular analysis of the PRO1 gene, which encodes gamma-glutamyl kinase. 135 Jul 80

We have recently published that soluble cytosolic glucocorticoid receptors are converted to a particulate form when they are incubated at 37 degrees C in a tubulin-polymerizing buffer [Pratt, W. B., Sanchez, E. R., Bresnick, E. H., Meshinchi, S., Scherrer, L. C., Dalman, F. C., & Welsh, M. J. (1989) Cancer Res. (Suppl.) 49, 2222s-2229s]. In this work, we further define this phenomenon and demonstrate that the L-cell glucocorticoid receptors are binding to a protein particulate composed largely of cytoskeletal proteins. Incubation of L-cell cytosol with glutamate at 37 degrees C converts the glucorticoid receptor to a form that pellets when cytosol is centrifuged at 150000g. The particulate material formed in a temperature-dependent and glutamate-dependent manner contains a large amount of tubulin, actin, and vimentin, but it is not the product of a cold-labile, colchicine-sensitive polymerization process. Very few cytosolic proteins are present in this complex, but the glucocorticoid receptor is tightly bound to it. Binding of the receptor to the cytoskeletal complex occurs after receptor transformation and is at least partially energy-dependent. Examination of the behavior of beta-galactosidase receptor fusion proteins and the nti glucocorticoid receptor demonstrates that residues 445 to the COOH-terminus of the receptor (DNA-binding and hormone-binding domains) contain the features required for binding to the cytoskeletal complex. Although it is the transformed receptor that associates tightly with the complex, DNA-binding activity is not required for association with the cytoskeletal particulate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Energy-dependent conversion of transformed cytosolic glucocorticoid receptors from soluble to particulate-bound form. 135 99

This report describes a novel mu chain capture ELISA for the detection of IgM antibodies against a Plasmodium falciparum antigen. A fragment of the 220 kDa P. falciparum glutamate rich protein containing amino acid residues 489-1271 was expressed in E. coli as a recombinant chimeric beta-galactosidase fusion protein and used as antigen after purification and biotinylation. Specific IgM antibodies were found in 51% (39/77) of sera from adult Liberians immune to malaria. The binding of IgM antibodies was specific for the malaria portion of the fusion protein and no cross-reactivity was found in sera from patients with IgM antibodies due to other diseases. Inhibition studies with a fusion protein containing amino acid residues 816-1134 (GLURP816-1134) representing the carboxy-terminal repeat region suggested a different use of epitopes for IgM antibodies in different individuals.
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PMID:Capture ELISA for IgM antibodies against Plasmodium falciparum glutamate rich protein. 143 Nov 49

A Plasmodium falciparum antigen gene coding for a 220-kD glutamate-rich protein (GLURP) has been cloned, and the 783 C-terminal amino acids of this protein (GLURP489-1271) have been expressed as a beta-galactosidase fusion protein in Escherichia coli. The encoded 783 amino acid residues contain two areas of repeated amino acid sequences. Antibodies against recombinant GLURP489-1271, as well as against a synthetic peptide corresponding to GLURP899-916, and against a synthetic peptide representing the major glutamate rich repeat sequence from the P. falciparum ring erythrocyte surface antigen (Pf155/RESA) (EENV)6 were examined in 423 individuals (age range 30 days-78 years) living in a malaria holoendemic area of Liberia. In the 5-9-year-old age group, subjects with anti-GLURP489-1271 antibody concentrations greater than the mean value of the group had lower parasite densities than those with low antibody concentrations (P = 0.0151). High levels of anti-GLURP899-916 antibodies did not correlate with low parasite densities. However, high levels of anti-(EENV)6 antibodies were associated with significantly lower parasite densities in the 2-4-year-old age group (P = 0.0189). There was no correlation between the anti-GLURP489-1271 and anti-(EENV)6 antibody responses. The data provide indirect evidence for a protective role of antibodies reacting with recombinant GLURP489-1271 as well as with the synthetic peptide (EENV)6 from the Pf155/RESA.
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PMID:Antibodies to a recombinant glutamate-rich Plasmodium falciparum protein: evidence for protection of individuals living in a holoendemic area of Liberia. 155 70

A transgenic mouse line containing a fos-lacZ fusion gene was derived in which beta-galactosidase activity identified cell populations expressing fos either constitutively or after stimulation. Seizures and light pulses induced nuclear lacZ activity in defined populations of neurons in vivo, and an array of neurotransmitters, including glutamate, induced the transgene in primary brain cultures. In unstimulated mice, the major sites of fos-lacZ expression were skin, hair follicle, and bone. fos-lacZ mice provide a new avenue for activity mapping studies based on gene expression.
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PMID:fos-lacZ transgenic mice: mapping sites of gene induction in the central nervous system. 173 4

A method for purification of a recombinant Plasmodium falciparum protein produced in E. coli and its use in an enzyme-linked immunosorbent assay (ELISA) is described. The cloned gene fragment encodes GLURP,489-1271 the carboxy-terminal 783 amino acid residue portion of a 1271 amino acid residue P. falciparum glutamate rich protein (GLURP), with a molecular weight of 220 kilodalton. The protein is associated with all parasite stages in the human host. Examination of sera from 105 adult Liberians living in a malaria endemic area revealed anti-GLURP IgG antibodies in 98% of the sera. The recombinant GLURP489-1271 was expressed as a chimeric protein, fused with E. coli beta-galactosidase. However, antibodies in sera were directed only against the malaria part of the fusion protein and not against beta-galactosidase. Antigen from in vitro P. falciparum cultures of isolates from Tanzania (F32), Papua New Guinea (MAD20) and Honduras (HB3) completely absorbed specific antibodies, indicating the presence of conserved epitopes produced by all isolates of P. falciparum. Recombinant GLURP489-1271 ELISA is sensitive and rapid, and therefore well-suited for sero-epidemiological studies, and for control of the immunogenicity of a possible future P. falciparum vaccine utilizing epitopes from GLURP.
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PMID:Recombinant Plasmodium falciparum glutamate rich protein; purification and use in enzyme-linked immunosorbent assay. 203 52


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