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:3.2.1.21 (beta-glucosidase)
3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carbaryl (1-naphthyl methylcarbamate), labeled with 14C in the C1-naphthyl, carbonyl, or N-methyl position, was introduced into the culture medium of tobacco cells in suspension culture. Following incubation, cells were homogenized in water, centrifugated, and supernatants hydrolyzed with beta-glucosidase or HCl. Organic moieties (moieties) were characterized by two-dimensional thin-layer chromatography (TLC), and many were subsequently identified by infrared and mass spectrometry. On the basis of the data obtained with 14C1-naphthyl-labeled carbaryl, it appeared that 18.4% of the total characterized metabolites represented unconjugated N-CH2OH- carbaryl [1-naphthyl N-(hydroxymethyl)carbamate], excreted by the cells into the culture medium. The metabolites found in the cells primarily consisted of conjugates of 1-naphthol (73.6% of the total characterized metabolites) and N-CH2OH-carbaryl (2.5%). Conjugates of 7-hydroxycarbaryl (7-hydroxy-1-napthyl methylcarbamate), 4-hydroxycarbaryl (4-hydroxy-1-naphthyl methylcarbamate), and 5-hydroxycarbaryl (5-hydroxy-1-naphthyl methylcarbamate) were also detected in small amounts. Of five unknown 14C1-naphthyl-labeled carbaryl metabolites, three were tentatively characterized as: O-1-naphthylcholesterol (Cholest-5-en-3beta-yl-1-napthol: 3.0%); an unconjugated hydroxylated 1,4-dihydro-1,4-epiperoxynapththalene (1.4%); and an acidlabile, beta-glucosidase-resistant conjugate of a cis-dihydrodiol of 1-naphthol (0.3%; other than the trans-5,6-dihydrodiol). The cholesterol derivative may represent a new "detoxification mechanism" in plants; the epiperoxide may help to elucidate plant oxidation mechanisms. A new TLC procedure was developed which successfully separated the acetate derivative of N-hydroxycarbaryl (1-naphthyl N-hydroxy-N-methylcarbamate) from 12 other common moieties of carbaryl metabolites and their acetate derivatives. A new two-dimensional TLC system was developed for the separation of underivatized N-hydroxycarbaryl from 14 other moieties of carbaryl metabolites; two additional two-dimensional TLC systems were utilized for moiety separations. With these TLC procedures, no conjugated or unconjugated N-hydroxycarbaryl could be detected in any tobacco cell culture fraction after incubation of cells in medium containing radiolabeled carbaryl. Authentic 14C1-naphthyl-labeled N-CH2OH-carbaryl was shown to be converted to desmethylcarbaryl (1-naphthylcarbamate) 97%) and 1-naphthol (3%) by 0.1N HCl hydrolysis.
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PMID:Identification by physical means of organic moieties of conjugates produced from carbaryl by tobacco cells in suspension culture. 81 72

Germinating cysts and isolated walls from germinating cysts incorporated 14C-UDPG into wall material of which 22.5 and 15% respectively were insoluble in boiling 1 N HCl, indicating that part of the synthetase activity is located in the wall itself. A combination of Urografin and Ficoll density gradients was used to separate various intracellular fractions. A consistent separation of beta-glucanase and UDPG-transferase enriched fractions was achieved. The beta-glucanase fraction contained dictyosome vesicles and fragments along with some plasma membranes. The UDPG-transferase fraction was relatively rich in membranes resembling rough and smooth ER. The results suggest the two enzymes are transported to the wall by different intracellular routes, and two types of vesicle may be involved. Alkaline phosphatase, beta-glucosidase and acid phosphatase were found extracellularly and their distribution in density gradients determined. The results of histochemical staining for acid phosphatase, alkaline phosphatase and polysaccharide are described and compared with the biochemical data. beta-1,3-glucanase, found intra- and extracellularly, induced distorted growth of germ tubes and also removed most of the apical wall when added to the incubation medium. None of these responses were observed with cellulase. Determinations of the osmotic pressure of germinating cysts and incubation medium revealed that the turgor of germinating cysts amounts to about 1.8 at under the conditions used.
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PMID:Hyphal tip growth in Phytophthora. Gradient distribution and ultrahistochemistry of enzymes. 101 47

In order to clarify some similarities and differences of decomposition modes between 20(S)-protopanaxadiol (20(S)-ppd) saponins, represented by ginsenoside Rb1 (Rb1) and ginsenoside Rb2 (Rb2), the decompositions of Rb1 and Rb2 in the rat gastrointestinal tract, 0.1 N HCl and crude hesperidinase were investigated in detail. As in the case of Rb2 reported previously, Rb1 was hydrolyzed to 20(R,S)-ginsenoside Rg3 in 0.1 N HCl. On the other hand, hydroperoxidation of Rb1 occurred in rat stomach; the major hydroperoxide was separated and identified as the 25-hydroperoxy-23-ene derivative of Rb1 (VIII) by 1H- and 13C-nuclear magnetic resonance and fast atom bombardment mass spectrometry. The decomposition modes of 20(S)-ppd saponins (Rb1 and Rb2) differed from that of 20(S)-protopanaxatriol saponin (Rg1) in rat stomach. In rat large intestine, five decomposition products of Rb1 were observed by thin-layer chromatography, and these were identified as gypenoside XVII (G-XVII), ginsenoside Rd (Rd), ginsenoside F2 (F2), compound K (C-K) and VIII. The decomposition modes of Rb1 and Rb2, both 20(S)-ppd saponins, are considered to be different because of the hydrolysis rate in the terminal sugar moiety at the C-20 hydroxyl group in the rat large intestine. Using crude hesperidinase, Rb1 was decomposed to G-XVII, F2 and C-K, and Rb2 was decomposed to 3-O-beta-D-glucopyranosyl-20-O-[alpha-L-arabinopyranosyl(1----6)-b eta-D- glucopyranosyl]-20-(S)-ppd, F2 and C-K. Consequently, it appears that hydrolysis by beta-glucosidase, which is present in the rat large intestine, is distinct from that by crude hesperidinase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies on absorption, distribution, excretion and metabolism of ginseng saponins. VII. Comparison of the decomposition modes of ginsenoside-Rb1 and -Rb2 in the digestive tract of rats. 180 49

Benzo[a]pyrene (BaP) undergoes metabolic transformation in mammals via oxidative, hydrolytic, and conjugative processes; however, little is known concerning BaP conjugation in freshwater algae. It has been shown in this laboratory that BaP is metabolized by Selenastrum capricornutum via a dioxygenase pathway. This study describes the conjugation of BaP metabolites by a green alga, Selenastrum capricornutum. Cultures were exposed to 1160 micrograms/l [14C]BaP for 4 days at 23 degrees C under gold fluorescent lights on a diurnal cycle of 16 h light, 8 h dark. Of the total metabolites in the algal culture, 89% were present in media. BaP and non-conjugated metabolites were separated from conjugated metabolites by chromatography on neutral alumina columns using solvents of increasing polarity. Seventy-one percent of the BaP metabolites were conjugates of which 12.2%, 12.0% and 12.4% were sulfate ester and alpha- and beta-glucose conjugates, respectively. Conjugates that coeluted with sulfate esters were hydrolyzed with arylsulfatase, alpha- or beta-glucosidase; high performance liquid chromatography (HPLC) analysis indicated that the major product of each enzymatic hydrolysis was the 4,5-dihydrodiol (87.2, 69 and 53%, respectively). Eighty-six percent of the conjugates were acid labile following incubation for 2 h in 4 N HCl at 37 degrees C. To our knowledge this is the first demonstration of the metabolism of a polynuclear aromatic hydrocarbon by a freshwater green alga through a dioxygenase pathway and subsequent conjugation and excretion.
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PMID:Conjugation of benzo[a]pyrene metabolites by freshwater green alga Selenastrum capricornutum. 210 10

M-GTFI, originally screened as an inhibitor of Streptococcus mutans glucosyltransferase, strongly inhibited alpha-glucosidase, in a non-competitive manner especially when the synthetic substrate p-nitrophenyl-alpha-D-glucopyranoside was used. It also inhibited beta-glucosidase, beta-amylase and, to a lesser extent, beta-glucuronidase. The inhibitor was stable in neutral and alkaline pH ranges and dependency of the inhibition on pH and temperature was not observed. Some proteinases and polysaccharides-hydrolyzing enzymes as well as human saliva did not inactivate the inhibitor. There was a correlation between the release of sulfate anions from the inhibitor molecule on incubation with HCl (0.2 N) at 100 degrees C and loss of inhibitory properties of the molecule. It is suggested that the presence of sulfate ester linkages in the inhibitor molecule play an important role in the inhibition process.
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PMID:Characteristics of M-GTFI, a new inhibitor of Streptococcus mutans glucosyltransferase. 297 50

The group O streptococcal group antigen was shown to be a polysaccharide located in the cell wall of the organism. The antigen could be extracted by one of several methods: (i) 0.5 n NaOH at 37 C, (ii) phenol-water (50:50) at 68 C, (iii) 0.2 n HCl at 100 C, or (iv) 10% trichloroacetic acid at 4 C. The last method yielded more polysaccharide with less protein contamination. The polysaccharide was purified on diethylaminoethyl-Sephadex A-25 and Sephadex G-200. It was composed of two-thirds glucosamine and galactosamine, and the remainder glucose plus galactose. Rhamnose, glycerol, ribitol, and muramic acid were absent. Total phosphorus and amino acids were each less than 0.1%. N-Acetyl-beta-d-glucosamine exerted a strong inhibition of the precipitin reaction and is considered the immunodominant sugar. Glucosamine and glucose possessed a partial inhibitory activity. Galactose and galactosamine were essentially negative. No evidence of cross-reactivity was found between the O polysaccharide and group A and L polysaccharides, and group A and Staphylococcus aureus teichoic acids, which posesss N-acetylglucosamine specificity. The release of limited quantities of N-acetyl-glucosamine from its terminal location by enzyme, and glucose by acid hydrolysis, indicates a limited number of side chains in the O antigen. The glucosamine is in acid-stable linkage in the polysaccharide. Glucose was not released by beta-glucosidase and probably does not occupy a terminal position. The O antigen is the only known streptococcal polysaccharide antigen which does not contain rhamnose. The effect of these factors on the immunological specificity is discussed. O serum, after adsorption with the purified polysaccharide, was used to demonstrate the presence of protein antigens in acid extracts of cells from each of the nine strains examined. These antigens may represent type antigens. Two of these strains, originally described as group O, did not contain the O polysaccharide.
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PMID:Chemical composition and immunological specificity of the streptococcal group O cell wall polysaccharide antigen. 462 49

The beta-glucosidases (EC 3.2.1.21) of Neurospora crassa were studied with respect to their location in conidia and young mycelia. Aryl-beta-glucosidase of conidia was nearly equally divided between extracellular and bound activity. Bound aryl-beta-glucosidase was almost all available to substrate. An induction procedure was used to maximize both beta-glucosidases in 4 to 6-hr cells. Aryl-beta-glucosidase was entirely bound but still mostly (90%) detectable, whereas cellobiase was mostly internal and cryptic. A freeze-thaw cycle or treatment with phenethyl alcohol or deoxycholic acid made the cellobiase detectable without releasing it from the cell. A 10 to 20% increase in cell-bound aryl-beta-glucosidase could be obtained by this treatment. Dilute HCl (0.1 n) destroyed the patent aryl-beta-glucosidase but not the cryptic aryl-beta-glucosidase or the cryptic cellobiase activity in intact cells. This suggested that most aryl-beta-glucosidase activity was exterior to the cell membrane but still within the mural space. The thermal stability of patent aryl-beta-glucosidase and released cellobiase was found to be higher than in corresponding cell-free extracts. Measurements of K(m) suggested a slightly lower affinity for substrate p-nitrophenyl-beta-d-glucopyranoside by the enzymes in intact cells compared to enzymes in extracts.
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PMID:Localization of the beta-glucosidases in Neurospora crassa. 541 19

Several beta-D-glucopyranosides (p-nitrophenyl, phenyl, and ethyl), 1-thio-beta-D-glucopyranosides, and phenyl 2-deoxy, 3-deoxy, 4-deoxy, and 6-deoxy beta-D-glucopyranosides were synthesized and used to study the mechanism of the enzymatic action of Taka-beta-glucosidase [EC 3.2.1.21 Aspergillus oryzae]. Kinetic constants of the enzyme for these glycosides were determined from S/V-S or 1/V-1/S plots, and the hydrolysis rates of these compounds with the enzyme, acid (3 N HCl) and alkali (3 N NaOH) were compared. Inhibition of the enzyme by 1,5-anhydroglucitol, glucal, dihydroglucal, and 1,6-anhydroglucopyranose was also examined. Glucal and 1,5-anhydroglucitol showed strong competitive inhibition. Free energy of binding of each hydroxyl group of glucosidic glucose with the enzyme was estimated from Kms of phenyl beta-glucoside and its deoxy analogues, and also Ki values of some inhibitors. The free energies of binding of 2-OH, 3-OH, 4-OH, and 6-OH were calculated to be 1.1, 2.4, 0.7, and 1.8 kcal/mol, respectively. The free energy of binding of phenoxide at C-1 (0.3 kcal/mol) was calculated from the Km of Ph-beta-Glc and Ki of 1,5-anhydroglucitol. The energy of binding of 5-CH2OH (2.3 kcal/mol) was obtained from the Km of Ph-beta-Glc and that of Ph-beta-Xyl. The sum (6.8 kcal/mol) of each partial binding free energy was close to the value of binding free energy of Ph-beta-Glc (7.0 kcal/mol) calculated by the equation; -delta Gbind = -RT ln Km-T delta Smix, showing that the methods of estimation of each binding energy used in the present study seemed reasonable. Glucal, having a pyranose form distorted slightly, showed strong competitive inhibition and the Ki of this inhibitor was smaller than the Km of Ph-beta-Glc, suggesting that the sugar ring bound to the active site was distored to a half chair form which is labile to acid hydrolysis.
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PMID:Energy of binding of Aspergillus oryzae beta-glucosidase with the substrate, and the mechanism of its enzymic action. 641 35

A pancreas cancer-associated antigen (PCAA) was identified and isolated from ascites fluid of human pancreatic cancer. Purified PCAA was homogeneous as determined by polyacrylamide gel electrophoresis. PCAA was a glycoprotein with a molecular weight of approximately 1,000,000 and consisted of 20% carbohydrates and 80% peptides, had an isoelectric point of 4.7, and migrated to alpha 2-beta region. It possessed a sedimentation coefficient of 14S and appeared to be a fibrous or fibroglobular protein. Immunoreactivity of PCAA was sensitive to proteolytic enzymes, perchloric acid, KSCN, glycine-HCl at pH 2.5, urea and lithium diiodosalicylate; and insensitive to neuraminidase or beta-glucosidase. Immunohistochemical technique revealed that PCAA was located in the cytoplasm of ductal epithelial cells of malignant pancreas. Using heteroantiserum raised against purified PCAA, horseradish peroxidase and CNBr-activated Sepharose 4B, an enzyme-immunoassay (EIA) for circulating PCAA has been developed. From a group of 40 healthy blood donors, an upper limit of 16.2 micrograms of PCAA/ml of serum has been tentatively determined. An elevated PCAA was shown in 67% (29/43) of patients with pancreas cancer, as well as in 30% (11/36) of lung cancer patients, 27% (10/37) of colonic cancer patients, and in 16% (6/36) of breast cancer patients. The reactive antigen in sera of these cancers was shown to be immunologically identical. PCAA also was detected in extracts of various human tissues, particularly pancreatic tumors, colonic tumors, and in a normal colon. Further, PCAA exhibited heterogeneity in molecular weight, isoelectric point, and electrophoretic mobility.
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PMID:Isolation, characterization and clinical evaluation of a pancreas cancer-associated antigen. 702 47

Previous studies have shown that Biomphalaria glabrata contains a complete cellulolytic system which includes an endoglucanase, an exoglucanase and a beta-glucosidase. In the present report, a scheme for the purification of the endoglucanase from this invertebrate is proposed. Two major problems were encountered during the study: 1) the presence of a green-brownish pigment, which could not be eliminated by thermal shock or ammonium sulfate precipitation and 2) relative instability of enzymatic activity. Various alternatives were tested and the best sequence of steps was: 1) a sample of the crude extract, obtained by homogenization of the digestive glands in 50 mM Tris-HCl buffer, pH 8.4, and ultracentrifugation, was applied to a Q-Sepharose FPLC column (50 mM Tris-HCl buffer, pH 8.4; 10 mm x 22.2 cm column; flow rate 1.5 ml/min; 0.1 to 0.5 M NaCl gradient); 2) the eluate peak containing activity was dialyzed, lyophilized and eluted from a Superdex-75 gel filtration FPLC column (50 mM ammonium acetate buffer, pH 4.8; 16 mm x 60 cm column; flow rate 1.0 ml/min). A low degree of purification (about 36-fold) and recovery (about 12%) were observed, probably due to enzyme instability. SDS-electrophoresis of the active fraction showed a major peak of 30 kDa. In order to improve the purification scheme, further studies are required to stabilize this enzyme during purification and storage.
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PMID:Partial purification of an endoglucanase from Biomphalaria glabrata. 754 74


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