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)

An alpha-amylase gene from Bacillus coagulans has previously been cloned in Escherichia coli and shown to direct the synthesis of an enzymically active protein of 60,000 Dal (Cornelis et al., 1982). In one particular E. coli host, strain HB101, amylase was found to accumulate in the periplasmic space. To study the processing and the location of the amylase, plasmid pAMY2 was introduced into E. coli 188 which is a strain constitutive for alkaline phosphatase, a periplasmic marker, and for beta-galactosidase, a cytoplasmic marker. Abnormally large amounts of both alpha-amylase and beta-galactosidase were found in the culture fluid of cells grown in rich medium. Furthermore a severe growth defect was found when cells containing pAMY2 were grown in maltose and glycerol media, while the ability to grow on glucose remained normal. This defect could be reversed by two types of spontaneous mutations. Mutations in the first class are located on the plasmid and correspond to the insertional inactivation of the amylase gene by IS1. Mutations in the second class are located on the host chromosome. These results suggest that the synthesis and export of B. coagulans alpha-amylase is deleterious to E. coli, especially in media containing maltose or glycerol as sole carbon source.
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PMID:Growth defects of Escherichia coli cells which contain the gene of an alpha-amylase from Bacillus coagulans on a multicopy plasmid. 618 99

Porcine rotaviral infectivity for continuous porcine kidney (PK-15) cells was enhanced by incorporation of pancreatic endopeptidases into the cell culture maintenance medium. Marked enhancement of infectivity was induced by trypsin, whereas elestase and alpha-chymotrypsin enhanced infectivity to a lesser extent. Bacterial protease also induced some enhancement of porcine rotaviral infectivity. A synergistic enhancement of porcine rotaviral infectivity was noticed with trypsin and alpha-chymotrypsin combined. Porcine rotaviral infectivity was not affected by incorporation of alpha-amylase, alkaline phosphatase, beta-galactosidase, carboxypeptidase-A, deoxyribonuclease, enterokinase, lipase, or ribonuclease into the maintenance medium.
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PMID:Porcine rotaviral infection of cell culture: effects of certain enzymes. 624 64

It is shown that segmented polyurethanes with D-lactose and D-maltose residues in the main polymer chain are subjected to a specific effect of enzymes: beta-galactosidase and alpha-amylase, respectively. This leads to a decrease in values of characteristic viscosity and physicomechanical indices of polyurethanes after their incubation with the mentioned enzymes. The compounds obtained are subjected to acid hydrolysis, which confirms sugar residues in the main polymer chain.
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PMID:[Enzymic segregation of segmented polyurethanes containing sugar residues in the composition of the main chain]. 641 80

1. The levels of the brush-border enzymes sucrase (sucrose glucohydrolase, EC 3.2.1.48), isomaltase (oligo-1,6-glucosidase, EC 3.2.1.10), maltases 2 and 3 (glucoamylase, EC 3.2.1.3), lactase (beta-galactosidase, EC 3.2.1.23) and trehalase (EC 3.2.1.28) and adsorbed pancreatic alpha-amylase (EC 3.2.1.1) have been measured at twenty-one positions along the small intestines of eighty-four pigs of different ages ranging from 3 weeks to 4.5 years. The state of dilation of the intestine at the sampling points was noted. 2. The levels of sucrase and isomaltase increased with age throughout the age-range studied. Trehalase and the glucoamylases increased with age up to 200--300 d of age. Lactase decreased with age over the whole age range. 3. For the pigs above 10 weeks of age, the distribution pattern of the brush-border enzymes along the intestine did not change with age. Each enzyme had a characteristic distribution curve, with low values at the proximal and distal ends and a peak which was proximal in the instance of lactase and trehalase and approximately mid-way along the gut with sucrase, isomaltase and the glucoamylases. 4. The pattern of distribution of the brush-border enzymes altered with age in the piglets, but approached the adult pattern by 8 weeks. 5. Piglets weaned at 3 weeks had higher levels of sucrase, isomaltase and glucoamylases at 5 weeks than piglets left on the sow. At 8 weeks of age the piglets weaned at 3 weeks still had higher sucrase and isomaltase levels than those on the sow. 6. There was a very close correlation between the sucrase and isomaltase levels, and between the maltase 2 and maltase 3 levels in all the samples, and a fairly close correlation between all these four enzymes. 7. The level of alpha-amylase increased with age but showed no regular distribution pattern, its irregular fluctuations being related to the presence or absence of dilation of the intestine at the time of slaughter rather than to the position along the intestine.
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PMID:The level of distribution of carbohydrases in the small intestine mucosa of pigs from 3 weeks of age to maturity. 696 56

An Aspergillus niger (An) genomic library was constructed using the promoter-trap vector, pLX2A, which contains a hygromycin B (Hy) phosphotransferase-encoding gene (hph) for selection of DNA fragments with promoter activity. This library was transformed in Escherichia coli and 80,000 colonies were obtained, 94% of which contained inserts. Transformations of plasmid DNA from the library into An resulted in 53 Hy-resistant (HyR) colonies. Southern blot analysis of 21 transformants confirmed the integration of hph into the An genome. Using the sib selection procedure, three functional promoters, PX6, PX18 and PX21, were identified from this library. Both DNA strands of all three fragments were sequenced and their sequences showed no significant homology to those in the database. Comparison of the sequences of all known promoters from An suggested that C+T-rich stretches are probably important for promoter structures. The promoter activity was analysed further using beta-galactosidase (beta Gal) as a quantitative marker. The results suggest that while PX21 is a much stronger promoter than the known alpha-amylase promoter of A. oryzae, PX6 promotes only weak expression of beta Gal.
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PMID:Cloning and characterization of three Aspergillus niger promoters. 755 61

We evaluated the effect of hemolysis, icteric discoloration, lipemia, paraproteinemia, and uremia on enzymatic methods for determining sodium, potassium, and chloride, according to the National Committee for Clinical Laboratory Standards EP7-P proposals for testing interference from endogenous substances. The sodium, potassium, and chloride assays (reagent kits supplied by Boehringer Mannheim) were based on electrolyte-dependent beta-galactosidase, pyruvate kinase, and alpha-amylase, respectively. The results were compared with those obtained by indirect ion-selective electrodes (ISE), which in turn had been validated by flame photometry. We analyzed the samples with Hitachi 717, 737, and 911 chemistry analyzers and with an IL943 flame photometer. The enzymatic results were in good agreement with those by ISE, the interference-related differences generally being without clinical significance; however, none of the enzymatic methods could analyze grossly lipemic samples.
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PMID:Enzymatic determination of sodium, potassium, and chloride in abnormal (hemolyzed, icteric, lipemic, paraproteinemic, or uremic) serum samples compared with indirect determination with ion-selective electrodes. 804 91

Rapid microtiter plate-based colorimetric assays have been developed that allow the screening of large numbers of samples for the presence of inhibitors of alpha-glucosidase, alpha-amylase, and beta-galactosidase. The assays are particularly useful for screening large numbers of microbial culture filtrates.
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PMID:High-throughput microtiter plate-based chromogenic assays for glycosidase inhibitors. 834 2

The adaptation and application of the Escherichia coli T7 RNA polymerase system for regulated and promoter-specific gene expression in Bacillus subtilis is reported. The expression cassette used in Bacillus subtilis was tightly regulated and T7 RnA polymerase (T7 RNAP)appeared 30 minutes after induction. The efficiency of T7 promoter-specific gene expression in B.subtilis was studied using one secretory and two cytosolic proteins of heterologous origin. The accumulation of E. coli beta-galactosidase, as well as a 1,4-beta-glucosidase from Thermoanaerobacter brockii in B. subtilis after T7 RNAP induction was strongly enhanced by rifampicin inhibition of host RNAP activity. The alpha-amylase of Thermactinomyces vulgaris, a secretory protein, was found to accumulate in the culture supernatant up to levels of about 70 mg/l 10-20 h after T7 RNAP induction, but was also deposited in cellular fractions. The addition of rifampicin inhibited chi-amylase secretion, but unexpectedly, after a short period, also prevented its further (intra)cellular accumulation.
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PMID:A T7 promoter-specific, inducible protein expression system for Bacillus subtilis. 862 23

Here, we report on the construction of three integrative plasmids for Bacillus subtilis (Bs) allowing in vitro construction of transcriptional fusions. These plasmids contain a neomycin- or tetracycline-resistance cassette and one of three promoterless genes: bgaB (encoding beta-galactosidase), cat (chloramphenicol acetyltransferase), or xylE (catechol 2,3-dioxygenase). All cassettes are flanked by the 3'- and 5'-ends of the amyE gene (encoding alpha-amylase) allowing integration of these cassettes at the amyE locus of the Bs chromosome. For propagation and selection in Escherichia coli, the plasmids contain the pBR322 origin of DNA replication and the beta-lactamase-encoding bla gene. Four unique restriction sites can be used for insertion of restriction fragments carrying promoter fragments. All three reporter genes express heat-stable enzymes (stable up to at least 50 degrees C for 30 min) as shown here. We would like to point to the modular nature of these plasmids where the three reporter genes and the two resistance cassettes can be combined in any permutation. The versatility of the promoter-probe vectors was demonstrated by the integration of the promoters of the dnaK and groE operons of Bs and following their heat-inducible expression.
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PMID:Integrative vectors for constructing single-copy transcriptional fusions between Bacillus subtilis promoters and various reporter genes encoding heat-stable enzymes. 898 64

The secretion of the heterologous parathion phosphotriesterase in S. lividans using the Streptomyces beta-galactosidase signal sequence was further characterised using a pulse/chase system. Unsecreted cell-associated protein in both the precursor and signal-cleaved forms was observed when the protein was expressed from both low- and high-copy vectors. Fractionation of the cells followed by immunoprecipitation with phosphotriesterase antibody suggests that the precursor is membrane-bound while the signal cleaved form is present in the soluble fraction. Preliminary data on the processing of alpha-amylase, a native streptomyces protein, showed much more rapid processing and secretion, but nevertheless still revealed cell-associated, signal-cleaved protein.
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PMID:Native and heterologous protein secretion by Streptomyces lividans. 898 22


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