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)

All- trans-retinoic acid (RA) contributes to the establishment of the anterior-posterior (AP) axis in chordates. In vertebrates, all- trans-retinol is oxidized to RA by two oxidative steps. However, the controversy about the enzymes responsible for retinol oxidation (ADH vs RDH) and the fact that some candidates are absent in cephalochordates questioned retinol oxidation in this lineage. Retinoid quantitation has revealed that Branchiostoma floridae adults contain both retinol and retinoic acid as well as retinal, the intermediate in the metabolic pathway. Furthermore, our data show that the developmental effects of retinol treatment are comparable to those reported for RA. SEM analysis revealed mouth and gill slit aberrations due to a posteriorization effect, also visualized by changes in the beta-galactosidase pattern. Overall, these findings support the idea that amphioxus metabolizes endogenous retinol to retinoic acid and suggest a common oxidative pathway for RA in the chordate phylum.
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PMID:Retinoic acid synthesis in the prevertebrate amphioxus involves retinol oxidation. 1220 95

A new coupling strategy using pre-packed diol-silica supports to obtain affinity columns for high-performance affinity chromatography (HPAC) is described. These columns were prepared by "in flow" activation in which solutions containing anhydrous solutions of CNBr and triethylamine are separately pumped to a mixer and then onto a pre-packed diol-silica column. Recycling the amino ligand to be coupled several times over the activated silica diol columns results in ligand immobilization. DNA (the Op 1 lac operator), 6-aminohexyl-Cibacron and a peptide (melittin) were all successfully "in flow" coupled to freshly activated columns. Methods for CNBr activation of pre-packed diol-silica column were developed for one, two or three pump HPLC systems. The supports were successfully used for the HPAC purification of a Lac repressor-beta-galactosidase fusion protein, alcohol dehydrogenase, and calmodulin. Columns prepared by in flow activation/coupling procedures were shown to be stable for at least 14 months. Also, in flow activated silica columns could be stored in anhydrous acetone for at least 3 months prior to coupling. Our experiments with these affinity ligand columns (DNA-silica, aminohexyl-Cibacron F3GA-silica, and melittin-silica), suggests that this is a very successful coupling protocol for producing a variety of HPAC columns.
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PMID:In flow activation of diol-silica with cyanogen bromide and triethylamine for preparing high-performance affinity chromatographic columns. 1256 72

Whole-mount detection methods are quick, inexpensive and offer the possibility of studying the temporal and spatial patterns of gene expression in a morphological context. These methods have been used widely to detect messenger RNAs and to measure enzymatic activity of reporter genes, such as beta-galactosidase or beta-glucuronidase. Taking advantage of the fact that NADH generated during the oxidation of formaldehyde by class III alcohol dehydrogenase can reduce the compound nitroblue tetrazolium to form a blue precipitate, we have developed a new method to detect class III alcohol dehydrogenase activity in situ in whole Arabidopsis plants. This reaction has been used earlier for in situ electrophoresis detection and for histochemical analysis in animal tissue sections. With a few modifications, it can be used in whole Arabidopsis plants or excised plant tissues to allow a rapid analysis of class III ADH activity during development or in response to elicitors. The method might be extended to other dehydrogenases by using specific substrates.
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PMID:Histochemical assay to detect class III ADH activity in situ in Arabidopsis seedlings. 1551 10

Freeze-induced perturbations of the protein native fold are poorly understood owing to the difficulty of monitoring their structure in ice. Here, we report that binding of the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS) to proteins in ice can provide a general monitor of ice-induced alterations of their tertiary structure. Experiments conducted with copper-free azurin from Pseudomonas aeruginosa and mutants I7S, F110S, and C3A/C26A correlate the magnitude of the ice-induced perturbation, as inferred from the extent of ANS binding, to the plasticity of the globular fold, increasing with less stable globular folds as well as when the flexibility of the macromolecule is enhanced. The distortion of the native structure inferred from ANS binding was found to draw a parallel with the extent of irreversible denaturation by freeze-thawing, suggesting that these altered conformations play a direct role on freeze damage. ANS binding experiments, extended to a set of proteins including serum albumin, alpha-amylase, beta-galactosidase, alcohol dehydrogenase from horse liver, alcohol dehydrogenase from yeast, lactic dehydrogenase, and aldolase, confirmed that a stressed condition of the native fold in the frozen state appears to be general to most proteins and pointed out that oligomers tend to be more labile than monomers presumably because the globular fold can be further destabilized by subunit dissociation. The results of this study suggest that the ANS binding method may find practical utility in testing the effectiveness of various additives employed in protein formulations as well as to devise safer freeze-drying protocols of pharmaceutical proteins.
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PMID:ANS fluorescence detects widespread perturbations of protein tertiary structure in ice. 1646 96

The objective of the present study was to characterize the metabolism of Clostridium thermolacticum, a thermophilic anaerobic bacterium, growing continuously on lactose (10 g l(-1)) and to determine the enzymes involved in the pathways leading to the formation of the fermentation products. Biomass and metabolites concentration were measured at steady-state for different dilution rates, from 0.013 to 0.19 h(-1). Acetate, ethanol, hydrogen and carbon dioxide were produced at all dilution rates, whereas lactate was detected only for dilution rates below 0.06 h(-1). The presence of several key enzymes involved in lactose metabolism, including beta-galactosidase, glyceraldehyde-3-phosphate dehydrogenase, pyruvate:ferredoxin oxidoreductase, acetate kinase, ethanol dehydrogenase and lactate dehydrogenase, was demonstrated. Finally, the intracellular level of NADH, NAD+, ATP and ADP was also measured for different dilution rates. The production of ethanol and lactate appeared to be linked with the re-oxidation of NADH produced during glycolysis, whereas hydrogen produced should come from reduced ferredoxin generated during pyruvate decarboxylation. To produce more hydrogen or more acetate from lactose, it thus appears that an efficient H2 removal system should be used, based on a physical (membrane) or a biological approach, respectively, by cultivating C. thermolacticum with efficient H2 scavenging and acetate producing microorganisms.
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PMID:Metabolism of lactose by Clostridium thermolacticum growing in continuous culture. 1650 46

Electron capture dissociation (ECD) offers many advantages over the more traditional fragmentation techniques for the analysis of peptides and proteins, although the question remains: How suitable is ECD for incorporation within proteomic strategies for the identification of proteins? Here, we compare LC-ECD-MS/MS and LC-CID-MS/MS as techniques for the identification of proteins. Experiments were performed on a hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. Replicate analyses of a six-protein (bovine serum albumin, apo-transferrin, lysozyme, cytochrome c, alcohol dehydrogenase, and beta-galactosidase) tryptic digest were performed and the results analyzed on the basis of overall protein sequence coverage and sequence tag lengths within individual peptides. The results show that although protein coverage was lower for LC-ECD-MS/MS than for LC-CID-MS/MS, LC-ECD-MS/MS resulted in longer peptide sequence tags, providing greater confidence in protein assignment.
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PMID:Liquid chromatography electron capture dissociation tandem mass spectrometry (LC-ECD-MS/MS) versus liquid chromatography collision-induced dissociation tandem mass spectrometry (LC-CID-MS/MS) for the identification of proteins. 1735 Feb 80

The reactive alpha-oxoaldehydes such as glyoxal (GO) and methylglyoxal (MG) are generated in vivo from sugars through oxidative stress. GO and MG are believed to be removed from cells by glutathione-dependent glyoxalases and other aldehyde reductases. We isolated a number of GO-resistant (GO(r)) mutants from Escherichia coli strain MG1655 on LB plates containing 10 mM GO. By tagging the mutations with the transposon TnphoA-132 and determining their cotransductional linkages, we were able to identify a locus to which most of the GO(r) mutations were mapped. DNA sequencing of the locus revealed that it contains the yqhC gene, which is predicted to encode an AraC-type transcriptional regulator of unknown function. The GO(r) mutations we identified result in missense changes in yqhC and were concentrated in the predicted regulatory domain of the protein, thereby constitutively activating the product of the adjacent gene yqhD. The transcriptional activation of yqhD by wild-type YqhC and its mutant forms was established by an assay with a beta-galactosidase reporter fusion, as well as with real-time quantitative reverse transcription-PCR. We demonstrated that YqhC binds to the promoter region of yqhD and that this binding is abolished by a mutation in the potential target site, which is similar to the consensus sequence of its homolog SoxS. YqhD facilitates the removal of GO through its NADPH-dependent enzymatic reduction activity by converting it to ethadiol via glycolaldehyde, as detected by nuclear magnetic resonance, as well as by spectroscopic measurements. Therefore, we propose that YqhC is a transcriptional activator of YqhD, which acts as an aldehyde reductase with specificity for certain aldehydes, including GO.
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PMID:Transcriptional activation of the aldehyde reductase YqhD by YqhC and its implication in glyoxal metabolism of Escherichia coli K-12. 2054 70


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