Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The P4 variant of Dictyostelium discoideum is characterized by the production of fruiting structures in which the overall proportion of stalk to spore material is increased, relative to the wild type. The altered morphology of the mutant is due to increased sensitivity to cyclic AMP which promotes stalk cell differentiation. In the presence of 10-4 M-cyclic AMP the entire population of P4 amoebae forms clumps of stalk cells on the surface of the dialysis membrane support. Measurement of changes in activity of a range of developmentally-regulated enzymes during the development of P4 in the presence and absence of cyclic AMP has allowed us to identify three classes of enzyme: (i) Those, such as beta-glucosidase II, trehalose-6-phosphate synthetase and uridine diphosphogalactose-4-epimerase, which are required for the production of spores. (ii) Enzymes, primarily but perhaps not exclusively, required during stalk cell formation. Typical of these are N-acetylglucosaminidase and alkaline phosphatase. (iii) General enzymes, such as threonine dehydrase, alpha-mannosidase and uridine diphosphoglucose pyrophyosphorylase, which are present inboth pre-stalk and pre-spore cells and appear to be necessary for the development of both cell types.
J Gen Microbiol 1975 Dec
PMID:Enzyme activity changes during cyclic AMP-induced stalk cell differentiation in P4, a variant of Dictyostelium discoideum. 17 91

Piromyces sp. strain E2, an anaerobic fungus isolated from an Indian elephant (hindgut fermenter) was tested for its ability to ferment a range of substrates. The fungus was able to use bagasse, cellobiose, cellulose, fructose, glucose, lactose, mannose, starch, wheat bran, wheat straw, xylan and xylose. Formate and acetate were the main fermentation products after growth on these substrates. The amount of carbon found in the fermentation products of cultures, in which substrate digestion was complete averaged 88.5 mM, or 59% of the carbon offered as substrate. No growth was observed on other substrates tested. Lactose, starch, cellobiose and filter paper cellulose were good inducers of cellulolytic and xylanolytic enzymes. Cellulolytic and xylanolytic enzymes were produced constitutively by Piromyces strain E2, although enzyme activities were generally lower after growth on glucose and other soluble sugars. Complex substrates (bagasse, wheat bran, and wheat straw) were good inducers for xylanolytic enzymes but not for cellulolytic enzymes. The extracellular protein banding pattern after SDS-PAGE was therefore only slightly affected by the growth substrate. Identical beta-glucosidase and endoglucanase activity patterns were found after growth on different substrates. This indicated that differences in enzyme activities were not the result of secretion of different sets of isoenzymes although it remains possible that the relative amount of each isoenzyme produced is influenced by the growth substrate.
J Gen Microbiol 1992 Aug
PMID:Production of cellulolytic and xylanolytic enzymes during growth of the anaerobic fungus Piromyces sp. on different substrates. 152 5

The stability and structure of the products of recombination in a fowlpox virus (FPV) system using the thymidine kinase (TK) gene as the insertion site were examined. A 4.6 kb chimeric DNA fragment from the pUV1 expression vector, containing the bacterial lacZ gene and the vaccinia virus P7.5 promoter, was ligated into the XbaI site of the FPV TK gene. The resulting vector, pFTKlacZb, was transfected into chicken embryo fibroblast cultures infected with FPV at an m.o.i. of 0.1. Recombinants were screened for the expression of beta-galactosidase. Five recombinants were isolated and plaque-purified to 80 to 90% for expression of beta-glucosidase. Serial cell culture passage of the recombinants led to the gradual reappearance of the non-recombinant parental phenotype. Southern hybridization analysis of EcoRI fragments from all five recombinants indicated that a single cross-over homologous recombination had occurred between either the 5' or the 3' end fragments of the TK gene, generating unstable intermediate recombinants incorporating the entire pFTKlacZb vector. Secondary intermolecular or intramolecular recombination of intergenic repetitive sequences within the intermediate recombinants appears to have resulted in frequent regeneration of the parental genotype and an infrequent generation of more stable recombinants. A method was developed to select stable recombinants by passage of the intermediate recombinants in chicken embryo fibroblast cultures treated with 5-bromo-2'-deoxyuridine.
J Gen Virol 1991 Nov
PMID:Structural analysis of unstable intermediate and stable forms of recombinant fowlpox virus. 165 7

Neocallimastix sp. NC71 and Piromyces sp. PC12 isolated from the calf remen grew optimally at 39 degrees C and pH 6.5-6.7, utilized a wide range of mono-, oligo- and polysaccharides and exhibited CMCase, Avicelase, cellobiase, amylase and xylanase activities. The end-products of wheat straw fermentation by both strains were acetate, formate, ethanol and lactate. The number of Neocallimastix sp. zoospores in the rumen of cows in the first 3 h after feeding with hay-silage-concentrate diets varied from 7 x 10(3) to 5.4 x 10(5) ml-1; the number of uniflagellate zoospores varied from 10(4) to 10(5) ml-1. Fungal zoosporgenesis and colonization of plant substrates in the rumen were induced by feed intake and were favoured by increased levels of crude fibre in the diet.
J Gen Microbiol 1991 Jul
PMID:Description of two anaerobic fungal strains from the bovine rumen and influence of diet on the fungal population in vivo. 195 64

Two enzymes that hydrolysed lactose were purified essentially to homogeneity from cell extracts of the oleaginous yeast Trichosporon cutaneum. One enzyme of Mr 120,000 had properties typical of a beta-galactosidase (EC 3.2.1.23). It hydrolysed lactose, lactulose and nitrophenyl-beta-D-galactosides. The enzyme required K+ or Rb+ for activity, and other monovalent cations tested were not effective. Enzyme activity was abolished by EDTA and stimulated by Mg2+, Mn2+ and Ca2+. The beta-galactosidase was induced by lactose, galactose, lactulose and lactobionic acid. The other enzyme, a beta-glycosidase (EC 3.2.1.21) of Mr 52,000 showed no ionic requirements and it hydrolysed lactose, nitrophenyl-beta-D-galactosides, 4-nitrophenyl-beta-D-glucoside, cellobiose, laminaribiose, laminaritriose and sophorose, but not gentiobiose, 4-nitrophenyl-beta-D-mannoside or sucrose. This enzyme was induced by lactose, galactose and lactulose, and also by cellobiose.
J Gen Microbiol 1990 Aug
PMID:Purification and properties of two lactose hydrolases from Trichosporon cutaneum. 212 10

The temperature and pH optima, and the temperature and pH stability, of crude and purified enzymes of the cellulase complex of the cellulolytic ascomycete fungus Neurospora crassa were investigated. The effects of some non-ionic surfactants and fatty acids on the production/release of enzymes of cellulase complex were also examined. For the different enzymes of the complex, activity maxima occurred between pH 4.0 and 7.0, with pH 5.0 being close to optimal for stability of all. Temperature optima for activity ranged between 45 and 65 degrees C, with the stability optimum between 45 and 50 degrees C. The presence of C18 fatty acids and surfactants resulted in increased production of both endoglucanase and exoglucanase in the medium. Oleic acid was the most effective fatty acid tested, and Tween 80 the most effective surfactant. Oleic acid had no detectable effect on production of beta-glucosidase, and Tween 80 actually reduced its production.
J Gen Microbiol 1990 Jul
PMID:The cellulase complex of Neurospora crassa: activity, stability and release. 214 64

The cloning, expression and nucleotide sequence of a 3.74 kb DNA segment on pLS215 containing a beta-glucosidase gene (bglA) from Butyrivibrio fibrisolvens H17c was investigated. The B. fibrisolvens bglA open reading frame (ORF) of 2490 bp encoded a beta-glucosidase of 830 amino acid residues with a calculated Mr of 91,800. In Escherichia coli C600(pLS215) cells the beta-glucosidase was localized in the cytoplasm and these cells produced an additional protein with an apparent Mr of approximately 94,000. The bglA gene was expressed from its own regulatory region in E. coli and a single mRNA initiation point was identified upstream of the bglA ORF and adjacent to a promoter consensus sequence. The primary structure of the beta-glucosidase showed greater than 40% similarity with a domain of 237 amino acids present in the beta-glucosidases of Kluyveromyces fragilis and Clostridium thermocellum. The B. fibrisolvens beta-glucosidase hydrolysed cellobiose to a limited extent, cellotriose to cellobiose and glucose, and cellotetraose and cellopentaose to predominantly glucose.
J Gen Microbiol 1990 Aug
PMID:Cloning, sequencing and analysis of expression of a Butyrivibrio fibrisolvens gene encoding a beta-glucosidase. 226 90

The nucleotide sequence of the bglB gene, coding for the thermostable beta-glucosidase B of Clostridium thermocellum was determined. The coding region of 2265 bp was identified by comparison with the N-terminal amino acid sequence of beta-glucosidase B purified from Escherichia coli. The derived amino acid sequence corresponding to a polypeptide of Mr 84,100 was confirmed by sequencing of the C-terminal peptide generated by cleavage with cyanogen bromide. The protein bears no resemblance to other bacterial beta-glucosidase sequences. However, extensive regions of homology were identified between the C. thermocellum enzyme and fungal beta-glucosidases. The N-terminal homologous region contains an amino acid sequence very similar to the active site of beta-glucosidase A3 from Aspergillus wentii. The striking sequence similarities between C. thermocellum beta-glucosidase B and Kluyveromyces fragilis beta-glucosidase suggest the possibility of a genetic exchange between thermophilic anaerobic bacteria and yeasts.
Mol Gen Genet 1989 May
PMID:Nucleotide sequence of the Clostridium thermocellum bgIB gene encoding thermostable beta-glucosidase B: homology to fungal beta-glucosidases. 250 54

A Streptomyces sp. isolated from compost degraded the hemicellulose fraction of straw efficiently but apparently not native cellulose. Ball-milled straw induced endoglucanase, beta-glucosidase, beta-xylanase and beta-xylosidase. Carboxymethylcellulose, cellotetraose and cellotriose induced cellulolytic enzymes specifically whereas cellobiose acted as inducer for beta-glucosidase only. Cellotriose and cellotetraose induced beta-glucosidase, but only partially induced endoglucanase. Hemicellulose (in the form of xylan) and xylobiose induced only beta-xylanase and beta-xylosidase. Kraft lignin and syringic acid induced beta-xylanase and endoglucanase but not the other enzymes. 3,4-Dimethoxycinnamic acid slightly induced beta-xylanase whereas 3,5-dimethoxy-4-hydroxycinnamic acid specifically induced endoglucanase. Neither veratric acid nor vanillic and ferulic acids induced any of the cellulolytic or hemicellulolytic enzymes. Enzyme production was subject to a form of carbon catabolite repression. Endoglucanase and beta-xylanase were excreted into the culture medium. Four protein components, one acidic (pI 5.2) and three basic (pI 8.15, 8.45 and 8.65) exhibited beta-xylanase activity. Two acidic components (pI 3.55 and 3.75) displayed endoglucanase activity.
J Gen Microbiol 1989 Feb
PMID:Regulation of the production of hemicellulolytic and cellulolytic enzymes by a Streptomyces sp. growing on lignocellulose. 251 44

The Lactococcus lactis subsp. lactis 712 lacG gene encoding phospho-beta-galactosidase was isolated from the lactose mini-plasmid pMG820 and cloned and expressed in Escherichia coli and L. lactis. The low phospho-beta-galactosidase activity in L. lactis transformed with high-copy-number plasmids containing the lacG gene contrasted with the high activity found in L. lactis containing the original, low-copy-number lactose plasmid pMG820, and indicated that the original lactose promoter was absent from the cloned DNA. In E. coli the phospho-beta-galactosidase could be overproduced using the strong inducible lambda PL promoter, which allowed a rapid purification of the active enzyme. The complete nucleotide sequence of the L. lactis lacG gene and its surrounding regions was determined. The deduced amino acid sequence was confirmed by comparison with the amino acid composition of the purified phospho-beta-galactosidase and its amino-terminal sequence. This also allowed the exact positioning of the lacG gene and identification of its characteristic Gram-positive translation initiation signals. The homologous expression data and the sequence organization of the L. lactis lacG gene indicate that the gene is organized into a large lactose operon which contains an intergenic promoter located in an inverted repeat immediately preceding the lacG gene. The organization and sequence of the L. lactis lacG gene were compared with those of the highly homologous lacG gene from Staphylococcus aureus. A remarkable bias for leucine codons was observed in the lacG genes of these two species. Heterogramic homology was observed between the deduced amino acid sequence of the L. lactis phospho-beta-galactosidase, that of the functionally analogous E. coli phospho-beta-glucosidase, and that of an Agrobacterium beta-glucosidase (cellobiase).
J Gen Microbiol 1989 Jul
PMID:Structure and expression of the Lactococcus lactis gene for phospho-beta-galactosidase (lacG) in Escherichia coli and L. lactis. 251 52


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