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 properties of seven enzymes were studied in extracts from Myxobacter AL-1. The enzymes were isocitrate dehydrogenase (E.C.1.1.1.42), succinate dehydrogenase (E.C.1.3.99.1), alkaline phosphatase (E.C.3.1.3.1), alpha-glucosidase (E.C.3.2.1.20), beta-glucosidase (E.C.3.2.1.21), beta-galactosidase (E.C.3.2.1.23), and N-acetyl-glucosaminidase (E.C. 3.2.1.30). Four of these enzymes: isocitrate dehydrogenase, alpha-glucosidase, beta-glucosidase, and beta-galactosidase are cytosolic enzymes. Succinate dehydrogenase was found to be located on the cytoplasmic membrane system, whereas alkaline phosphatase and N-acetylglucosaminidase were considered as enzymes which bind the outer membranes resp. the cell wall. During the cell cycle, all enzymes have a pattern of discontinuous activity increase. Succinate dehydrogenase and isocitrate dehydrogenase exhibit a stepwise increase of activity, whereas the other enzymes follow the pattern of a peak enzyme.
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PMID:Studies on the cell cycle of Myxobacter AL-1. II. Activities of seven enzymes during the cell cycle. 2 Aug 61

We report a phenomenon similar to catabolite repression in Rhizobium meliloti. Succinate, which allows the highest observed rate of growth of R. meliloti, caused an immediate reduction of beta-galactosidase activity when added to cells growing in lactose. A Lac- mutant was unaltered in nodulation and nitrogen fixation capacities, but a pleiotropic mutant deficient in several catabolic properties was unable to produce effective nitrogen-fixing nodules.
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PMID:Catabolite-repression-like phenomenon in Rhizobium meliloti. 21 20

Tetrahymena were grown in proteose-peptone medium supplemented with glucose, mannose, fructose, galactose, acetate, succinate, or pyruvate and then washed and resuspended in a non-nutrient salt solution and the amounts of 7 acid hydrolases secreted into the medium in a one hour incubation were measured. Cells that had been grown in the presence of glucose secreted about half the amounts of acid phosphatase, beta-N-acetylglucosaminidase and acid protease as did control cells grown in unsupplemented medium. Pyruvate was about as effective as glucose and both were slightly more effective than acetate or fructose. Succinate had little effect. Similar experiments showed that alpha-mannosidase, beta-fucosidase, and beta-galactosidase are secreted into the salt solution and the secretion is reduced by prior growth of the cells in medium supplemented with glucose or mannose but not galactose. Except for alpha-mannosidase, these reductions in amounts of hydrolase secreted were not accompanied by appreciable changes in intracellular activity, and therefore demonstrate a persistent effect of growth in the presence of certain metabolites on the subsequent secretion of lysosomal hydrolases. Since the inhibition of subsequent secretion depended on both the individual metabolite and the particular hydrolase examined, it appears that the effect of metabolites is not limited to a general inhibition of secretion but may differentially alter some properties of lysosomal subpopulations. A preliminary characterization of the secreted acid protease of Tetrahymena suggests that there may be two acid proteases released, since up to 25% of the activity was not inhibited by high concentrations of pepstatin, leupeptin, or chymostatin.
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PMID:Effects of metabolites present during growth of Tetrahymena pyriformis on the subsequent secretion of lysosomal hydrolases. 80 52

A selection procedure using Mn2+ is described. A high percentage of the Mn2+ resistant mutants had constitutive iron transport systems. By P1 transduction, and complementation with the cloned fur gene it could be shown that nearly all the mutants constitutive in the expression of the operon fusion fiu::lambda placMu were only defective in fur. High concentrations of manganese inhibited the derepression of an iron-regulated lac operon fusion. In another iron-regulated lac operon fusion that was inducible by iron, manganese also induced the production of beta-galactosidase. Most of the fur mutants isolated (80%) were not able to grow on succinate, fumarate or acetate. After transformation with a fur+ plasmid all 39 mutants tested were able to grow on succinate. In fur mutants the presence of succinate in the growth medium reduced succinate uptake rates by 50%-70%. Succinate dehydrogenase activity was reduced to 10% of that of the parent strain.
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PMID:Selection procedure for deregulated iron transport mutants (fur) in Escherichia coli K 12: fur not only affects iron metabolism. 332 34

Severe transient repression of constitutive or induced beta-galactosidase synthesis occurs upon the addition of glucose to cells of Escherichia coli growing on glycerol, succinic acid, or lactic acid. Only mutants particularily well adapted to growth on glucose exhibit this phenomenon when transferred to a glucose-containing medium. No change in ribonucleic acid (RNA) metabolism was observed during transient repression. We could show that transient repression is pleiotropic, affecting all products of the lac operon. It occurs in a mutant insensitive to catabolite repression. It is established much more rapidly than catabolite repression, and is elicited by glucose analogues that are phosphorylated but not further catabolized by the cell. Thus, transient repression is not a consequence of the exclusion of inducer from the cell, does not require catabolism of the added compound, and does not involve a gross change in RNA metabolism. We conclude that transient repression is distinct from catabolite repression.
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PMID:Transient repression of the lac operon. 486 11

Strain 130ZT was isolated from the bovine rumen. It is a facultatively anaerobic, pleomorphic, Gram-negative rod. It exhibits a 'Morse code' form of morphology, which is characteristic of the genus Actinobacillus. Strain 130ZT is a capnophilic, osmotolerant succinogen that utilizes a broad range of sugars. It accumulates high concentrations of succinic acid (> 70 g l-1). Strain 130ZT is positive for catalase, oxidase, alkaline phosphatase and beta-galactosidase, but does not produce indole or urease. Acid but no gas is produced from D-glucose and D-fructose. 16S rRNA sequence analysis places strain 130ZT within the family Pasteurellaceae; the most closely related members of the family Pasteurellaceae have 16S rRNA similarities of 95.5% or less with strain 130ZT. Strain 130ZT was compared with Actinobacillus lignieresii and the related Bisgaard Taxa 6 and 10. Based upon morphological and biochemical properties, strain 130ZT is most similar to members of the genus Actinobacillus within the family Pasteurellaceae. It is proposed that strain 130ZT be classified as a new species, Actinobacillus succinogenes. The type strain of Actinobacillus succinogenes sp. nov. is ATCC 55618T.
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PMID:Actinobacillus succinogenes sp. nov., a novel succinic-acid-producing strain from the bovine rumen. 1002 65

A new species, Porphyromonas gulae sp. nov., is proposed to include strains isolated from the gingival sulcus of various animal hosts which are distinct from related strains of Porphyromonas gingivalis of human origin. This bacterium exhibits the following characteristics: black-pigmented colonies; asaccharolytic, obligate anaerobic growth; and Gram-negative, non-motile and non-spore-forming, rod-shaped cells. Colonies do not fluoresce under UV light. Vitamin K1 and haemin are required for growth. Cells haemagglutinate sheep erythrocytes. Major fatty acid end products are butyric acid, isovaleric acid, succinic acid and phenylacetic acid. Strains are catalase-positive and indole is produced. Alkaline phosphatase, trypsin-like and N-acetyl-beta-glucosaminidase activities are strong. A beta-galactosidase and a glutamylglutamic acid arylamidase are also present. The G+C content of the chromosomal DNA is 51 mol%. DNA-DNA homology data and 16S rRNA gene sequence analysis provide strong evidence that strains from the animal biotype of P. gingivalis represent a Porphyromonas species that is distinct from P. gingivalis. The type strain of P. gulae is Loup 1T (= ATCC 51700T = NCTC 13180T).
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PMID:Porphyromonas gulae sp. nov., an anaerobic, gram-negative coccobacillus from the gingival sulcus of various animal hosts. 1141 86

A reliable enzyme immunoassay (EIA) method was developed for quantitative determination of aconitine with high sensitivity and specificity. The bovine serum albumin (BSA)- and beta-galactosidase (beta-Gal) conjugates as immunogens and enzyme-labeled antigens were prepared by coupling of their proteins with succinic acid (short chain length; n=2, where n represents the number of methylene units) and hexadecanedioic acid (long chain length; n=14) hemiesters of benzoylaconine through the respective N-hydroxysuccinimide esters as intermediates. Two types of the BSA-conjugates with short and long chains were repeatedly injected into rabbits to obtain anti-aconitine antisera (As1 and As2, respectively). All combinations of beta-Gal-labeled antigens LAg1 (n=2) and LAg2 (n=14) with antisera As1 (n=2) and As2 (n=14) showed high sensitivity to aconitine in a range of 0.1-1.0 ng. Although the combination of LAg2 (n=14) with antiserum As1 (n=2) showed high specificity to aconitine, the combination of LAg2 (n=14) and As2 (n=14) was highly specific to both aconitine and mesaconitine. When aconitine was intravenously administered to rats, the aconitine concentration in their plasma remarkably decreased within the first 60 min, and then gradually declined, suggesting a two-compartment pharmacokinetic model in (V(c) 0.41+/-0.09 l/kg, V(dss) 1.7+/-0.4 l/kg, CL(tot) 10+/-2 ml/min x kg, AUC(0-4800) 2055+/-294.3 ng x min/ml). Following oral administration of aconitine to rats at two doses of 0.1 and 1.0 mg/kg b.w., the maximum plasma concentrations (C(max)) were 0.73+/-0.08 and 3.3+/-0.6 ng/ml at times of 45+/-9 and 150+/-52 min, respectively, and the AUC(0-1440) values were 130+/-4 and 1600+/-270 ng x min/ml. The bioavailability (F) of aconitine was determined to be 0.013, where only 1.3% of the aconitine administered orally was absorbed into the body fluid.
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PMID:A new enzyme immunoassay for aconitine and its application to quantitative determination of aconitine levels in plasma. 1295 73

1. An experimental system suitable for the study of enzyme formation has been described. 2. The formation of beta-galastosidase in E. coli B could be induced by lactose, melibiose, D-galactose and beta-methyl-D-galactoside. 3. Lactose-induced beta-galactosidase formation was found to be inhibited by D-glucose, D-mannose, D-fructose, D-arabinose, and raffinose. 4. The utilizable structural analogue, D-glucose, was found to either stimulate or inhibit beta-galactosidase formation depending upon its concentration. D-Arabinose, on the other hand, a non-utilizable structural analogue, is only capable of inhibiting, whereas succinic acid, a structurally unrelated energy source, is only capable of stimulating beta-galactosidase formation. 5. D-Arabinose inhibition of lactose-induced beta-galactosidase formation was found to be of the competitive type. 6. Some of the implications of these findings have been discussed.
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PMID:The mechanism of the synthesis of enzymes. I. Development of a system suitable for studying this phenomenon. 1305 5