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 problem of melaninogenesis and quinone tanning of the cuticle was examined by histochemical and biophysical methods (electroparamagnetic resonance: EPR) on normal subjects of Pycnoscelus surinamensis and on subjects with abnormal cuticular colour. The cuticle of abnormal subjects showed a lower content of polyphenolic substances and a greater positivity for the indole group. This suggests that in these insects tanning products can be synthetized differently and not derived from tyrosine but from tryptophan as postulated by Pryor (1955). Furthermore, a higher number of unsaturated aminic groups is found in abnormal subjects. Granules present only in the cytoplasm of the epidermal cells of the abnormal newly moulted subjects may indicate that the polyphenolic compound of tanning, secreted in an inactive form as 4-0, beta-glucoside, is not freed from the beta-glucosidase and remains as such in the cytoplasm.
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PMID:Histochemical and biophysical study of cuticle sclerotization in Pycnoscelus surinamensis L. (Blattaria). 4 33

Only L-ascorbic acid activated plant myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1), whereas ascorbic acid analogs did not. The enzyme protein was conformationally changed by the addition of L-ascorbic acid to the spectrophotometric analysis, approx. 1.5 amino residues appeared on the surface of the enzyme and about 2.3 tryptophan residues were buried in the molecule when 1 mM L-ascorbic acid was added. Optimum temperature for the myrosinase activity was approx. 55 degrees C without L-ascorbic acid, but with L-ascorbic acid it was about 35 degrees C; that for beta-glucosidase activity was the same (55 degrees C) with or without L-ascorbic acid. The effect of chemical modification of the functional groups of myrosinase on the interaction of L-ascorbic acid was investigated and the interaction of L-ascorbic acid with the active center of the enzyme is proposed.
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PMID:The interaction of L-ascorbic acid with the active center of myrosinase. 10 23

The problem of melaninogenesis and quinone tanning of the cuticle was examined by histochemical and biophysical methods (electroparamagnetic resonance: EPR) on normal subjects of Pycnoscelus surinamensis and on subjects with abnormal cuticular colour. The cuticle of abnormal subjects showed a lower content of polyphenolic substances and a greater positivity for the indole group. This suggests that in these insects tanning products can be synthetized differently and not derived from tyrosine but from tryptophan as postulated by Pryor (1955). Furthermore, a higher number of unsaturated aminic groups is found in abnormal subjects. Granules present only in the cytoplasm of the epidermal cells of the abnormal newly moulted subjects may indicate that the polyphenolic compound of tanning, secreted in an inactive form as 4-O, beta-glucoside, is not freed from the beta-glucosidase and remains as such in the cytoplasm.
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PMID:Histochemical and biophysical study of cuticle sclerotization in Pycnoscelus surinamensis L. (Blattaria). 53 16

A total of 32 strains of the family Leptospiraceae (23 strains of Leptospira interrogans, 6 strains of Leptospira biflexa, 2 strains of Leptonema and 1 strain of Leptospira parva) were examined for enzyme activities using 89 substrates (API ZYM system). More than 90% of the strains belonging to the family Leptospiraceae possessed strong activities of beta-D-galactosidase, beta-D-glucosidase and 5 esterases (C5, C6, C8, C9 and C10). More than 90% of the strains belonging to the genus Leptospira, except L. parva, had strong activities of L-lysine arylamidase and alpha-L-glutamate arylamidase. L. biflexa strains, except serovar andamana, were different from the other strains examined in that they possessed glycyl-glycine arylamidase, glycyl-phenylalanine arylamidase and L-tryptophan arylamidase. L. biflexa strains, except andamana, L. parva and Leptonema strains possessed strong activities of glycine arylamidase and leucyl-glycine arylamidase. Two strains of the genus Leptonema were different from the strains belonging to the genus Leptospira in that they possessed strong activities of beta-D-lactosidase. L. parva lacked alpha-D-galactosidase which other strains belonging to the family Leptospiraceae possessed. Dendrogram analysis revealed that strains belonging to the family Leptospiraceae were divided into 4 groups. The first group consisted of all strains belonging to L. interrogans and serovar andamana of L. biflexa; the second group consisted of the remaining 5 serovars of L. biflexa; the third group consisted of the genus Leptonema; and the fourth group consisted of only L. parva.
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PMID:Enzyme activities of the strains belonging to family Leptospiraceae detected by the API ZYM system. 289 26

We compared the concentrations of protein-unbound non-tryptophan fluorescent substances in the water-soluble fraction between non-brunescent (NBr) and brunescent (Br) human cataractous lens nuclei. Lens nuclei (NBr, 22 eyes: Br, 9 eyes) from non-diabetic patients, obtained by extracapsular cataract extraction, were individually homogenized and centrifuged. The supernatants were subsequently ultra-dialyzed and assessed by high pressure liquid chromatography. 3-Hydroxykynurenine-O-beta-glucoside (3-HKG) as well as an unidentified fluorescent substance was detected. While the concentrations of the former substance did not significantly differ between the NBr and the Br nuclei (NBr, 0.55 +/- 0.49 mumol/g wet weight: Br, 0.90 +/- 0.64 mumol/g wet weight; p > 0.1), the concentration of the latter substance was significantly greater in the Br nuclei than in the NBr nuclei (NBr, 2.2 x 10(3) +/- 5.4 x 10(3) AU/g wet weight: Br, 1.4 x 10(5) +/- 1.1 x 10(5) AU/g wet weight; AU: area unit, p < 0.01). An incubation of the dialysate with beta-glucosidase eliminated the peak corresponding to the latter substance. These results suggest that an unidentified protein-unbound fluorescent substance, which is presumably a beta-glucoside, in the lens nuclei is related to the coloration of human lens nuclei.
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PMID:[Comparison of free non-tryptophan fluorescent substances in water-soluble fraction of brunescent and non-brunescent human cataract]. 865 Oct 55

Carboxymethylcellulase (CMCase) was extracted and purified from an angiosperm parasite Cuscuta reflexa free from beta-glucosidase and other enzyme activities. The molecular mass and Stokes' radius of the purified enzyme are 144 kDa and 44 A, respectively. The diffusion coefficient and frictional ratio of the enzyme were 5.15 x 10(-7) cm2/sec and 1.27. The SDS-PAGE revealed homotetrameric nature of the enzyme with a subunit molecular mass of 35 +/- 1 kDa. Titration against DTNB and NBS revealed 19 sulfhydryl groups and 8 tryptophan groups, respectively, per mole of the enzyme. A sharp pH optimum at 5.0 was obtained. Cuscuta CMCase activity is unique amongst plant endoglucanases in being stimulated by Mg2+ and Mn2+ ions and by various thiols. Reaction product analysis, mode of enzyme action and substrate specificity test suggest the endo- nature of the purified CMCase. The enzyme showed K(m) value of 26 +/- 1 mg/ml for carboxymethylcellulose (sodium salt).
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PMID:Physico-chemical and functional characterization of a high molecular weight carboxymethylcellulase from Cuscuta reflexa. 949 45

The production of the extracellular cellulolytic enzyme system (endoglucanase, exoglucanase and cellobiase) of N. catalinensis was tested with different nitrogen sources, inorganic and organic ones, in liquid culture medium with microcrystalline cellulose. The nitrogen compounds used were: potassium nitrate, sodium nitrate, ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium tartrate, urea, casamino acids, glycine, L-alanine, L-leucine, L-proline, L-lysine, L-aspartic acid, L-glutamic acid, L-asparagine, L-glutamine, L-phenylalanine, L-tyrosine, L-tryptophan, L-methionine and L-cysteine. Among these, ammonium nitrate and ammonium tartrate gave the highest yields of cellulases in 20-day-old cultures at a concentration equivalent to 0.75 g N/l in both cases. Optimal temperature for cellulase production, growth and cellulose degradation was 23 degrees C. On the other hand, an initial pH of 6.5 gave the highest yields of endoglucanase and cellobiase. In the same way, at pH 6.5, maximal growth and cellulose degradation were achieved. However, maximal exoglucanase production and glycogen content were reached at pH 7.5.
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PMID:Influence of different cultural conditions on cellulase production by Nectria catalinensis. 962 4

An extracellular xylanase was purified to homogeneity from the culture filtrate of a thermophilic fungus, Thermomyces lanuginosus-SSBP, and its biochemical characteristics were studied. A yield of 70-80% was achieved through the procedures of 80%-satd. ammonium sulphate precipitation, DEAE-Sephadex A25 and quaternary aminoethyl (QAE)-Sephadex A25 column chromatography. The molecular mass of the purified xylanase was 23.6 kDa, as analysed by SDS/PAGE, with a pI value of 3.8. The molar absorption coefficient of the absorbance at 280 nm was 6.8x10(4) M(-1).cm(-1). The specific activity, calculated using the dinitrosalicylic acid (DNS) method, was 3500 units/mg. The enzyme reactions followed Michaelis-Menten kinetics with K app m and V(max) values of 3.26 mg/ml and 6300 units/ml per mg of protein respectively, as obtained from a Lineweaver-Burk plot. The xylanase contained no other enzyme activity (cellulase, beta-glucosidase, beta-mannosidase, alpha-arabinofuranosidase, or beta-xylosidase) except for the hydrolysis of xylan substrate. The optimal temperature of the enzyme assay was 70-75 degrees C. The enzyme retained full activity after a 60 degrees C incubation for 3 h. The optimal pH of xylanase activity was 6.5 and the enzyme appeared to be stable over a broad pH range (pH 5-12) under the assay conditions. The majority of the metal ions tested had no effect on the enzyme activity, with the exception of Pb(2+) (modest inhibitor) and Hg(2+) (strong inhibitor). The results showed that one or two tryptophan residues oxidized by N-bromosuccinamide per enzyme molecule was sufficient to inhibit the enzyme activity completely, thus indicating that the tryptophan residues play an important role in the catalytical processes of the enzyme reaction. Because of the outstanding properties of the purified xylanase from the SSBP strain, this xylanase has a potential use in biopulping processes and other industrial applications.
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PMID:Purification and biochemical characteristics of beta-D-xylanase from a thermophilic fungus, Thermomyces lanuginosus-SSBP. 1046 22

This study determined whether Astragalus lusitanicus inhibits glycosidase enzymes other than alpha-mannosidase. Plasma collected from lambs given fresh A lusitanicus inhibited beta-glucosidase and beta-galactosidase, indicating the presence of inhibitors in their blood. The residual activity of these enzymes was also modified in tissues of dead animals. beta-glucosidase activity was reduced in liver and kidney specimens with pronounced effects in tissues of animal that presented with prominent clinical signs of poisoning; beta-galactosidase activity was decreased by 88.5 to 95% in kidney, while that of liver remained unchanged. Fractions of the plant butanol extract inhibited the gycosidase enzymes. Chemical analysis revealed the presence of hypaphorin in the extract of A lusitanicus. As a tryptophan derivative, this alkaloid may play a role in the toxicity of this legume.
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PMID:Inhibition of glycosidases by Astragalus lusitanicus and correlation with toxicity. 1157 29

A gene encoding a putative beta-glucosidase was isolated from Thermoascus aurantiacus IFO9748 and designated as bgl2. The recombinant enzyme showed beta-glucosidase activity when p-nitrophenyl-beta-glucose (pNP-Glc) was used as substrate. We also found that the enzyme activity was increased in the presence of organic solvents. An addition of 20 % (v/v) 1-octanol resulted in 54-fold higher activity of pNP-Glc hydrolysis, and transglycosylation activity was also found to be activated. The results of tryptophan fluorescence spectral analysis revealed the changes in the tertiary structure of the enzyme in the presence of 1-hexanol that may cause increased enzyme activity. BGLII has a distinctive hydrophobic linker region between N- and C-terminal domains. A chimeric enzyme in which the linker region was substituted by the corresponding region of another beta-glucosidase failed to be activated by organic solvents, suggesting that the hydrophobic linker region may act as a molecular switch in BGLII.
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PMID:Unusual hydrophobic linker region of beta-glucosidase (BGLII) from Thermoascus aurantiacus is required for hyper-activation by organic solvents. 1661 58


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