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

Sugar specific lectins (PNA, RCA I, LPA, SBA, DBA, GSA IB4, GSA II, WGA, LTA, UEA I, Con A, LCA) with and without prior selective glycosidase digestion (sialidase, alpha-fucosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, alpha- and beta-galactosidase, beta-glucosidase) were used in order to investigate the distribution of native accessible carbohydrates and obtain information dealing with the composition of terminal disaccharides within glycoconjugates present in acinar compartments and ductal segments of mammalian (mouse, rat, hare, and rabbit) parotid glands. Glycoconjugates containing variable amounts of mannose, glucose, N-acetylgalactosamine and N-acetylglucosamine were present in the parotid glands of all species. However, these carbohydrate chains exhibited a different composition of terminal sequences within each type of gland. For example, sialylated components having the terminal dimers sialic acid-galactose and sialic acid-N-acetylgalactosamine were found in all acinar cells, whereas fucoglycoconjugates with terminal disaccharide fucose-galactose were localized in the rat striated ducts and hare acinar cells. The terminal sequence alpha-galactose-beta-galactose was demonstrated in the mouse acinar cells. Finally, glycoconjugates characterized by the terminal dimer beta-galactose-N-acetylgalactosamine were demonstrated in the mouse acinar and ductal cells and the rat ductal ones. Thus, present findings outlined and further confirmed the possibility to elucidate the oligosaccharide structure in situ using lectin histochemistry combined with enzymatic degradation.
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PMID:Glycoconjugate composition of mammalian parotid glands elucidated in situ by lectins and glycosidases. 137 7

alpha-D-Mannosidase and beta-D-glucosidase from Dictyostelium discoideum are efficiently endocytosed into mutant human fibroblasts through a saturable, mannose 6-phosphate (Man-6-P)-inhibitable uptake system (Freeze, H. H., Kaplan, A., and Miller, A. L. (1980) J. Biol. Chem. 255, 11081-11084). We have extended this study using both of these active, purified enzymes and 125I-labeled beta-glucosidase for uptake into normal human fibroblasts. The pH optimum of uptake is 6.0 for both enzymes and greater than 95% is inhibited by 2 mM Man-6-P (Ki = 5 X 10(-5) M). A variety of mono-and diesterified mannans or mannan derivatives also inhibited uptake of the enzymes. Both enzymes compete with each other for uptake (Ki, 2.0 X 10(-9) M) and have Kuptake of 1.0-2.2 X 10(-9) M and a Vmax of 0.35-0.48 pmol/mg of cell protein/h. The specific binding of 125I-beta-glucosidase to fibroblasts was measured at 0-4 degrees C and found to have a Kd of 1.0 X 10(-9) M with approximately 15,900 +/- 900 receptors/cell. The receptors could be internalized every 5-7 min at saturating concentrations of enzyme at 37 degrees C. The 125I-beta-glucosidase previously bound to the cells at 4 degrees C could be released by continued incubation at 4 degrees C in the presence of Man-6-P, however, after brief warming to 37 degrees C followed by reincubation at 4 degrees C, Man-6-P could no longer release the ligand. Chloroquine inhibited 95% of the uptake of 125I-beta-glucosidase at 50 microM. Following internalization of the enzyme, it is degraded to trichloroacetic acid-soluble fragments with a half-life of approximately 6.5 h. These data suggest that the slime mold enzymes are bound to the same receptors which function in the uptake of mammalian lysosomal enzymes and make the slime mold lysosomal enzymes useful models to study uptake involving this receptor in normal human fibroblasts.
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PMID:Uptake of alpha-D-mannosidase and beta-D-glucosidase from Dictyostelium discoideum via the phosphohexosyl receptor on normal human fibroblasts. 630 4

Little is known about the potential of enzyme activities, which are sensitive to soil properties and management, for the characterization of dust properties. Enzyme activities may be among the dust properties key to identifying the soil source of dust. We generated dust (27 and 7 microm) under controlled laboratory conditions from agricultural soils (0-5 cm) with history of continuous cotton (Gossypium hirsutum L.) or cotton rotated with peanut (Arachis hypogaea L.), sorghum [Sorghum bicolor (L.) Moench], rye (Secale cereale L.), or wheat (Triticum aestivum L.) under different water management (irrigated or dryland) and tillage (conservation or conventional) systems. The 27- and 7-microm dust samples showed activities of beta-glucosidase, alkaline phosphatase, and arylsulfatase, which are related to cellulose degradation and phosphorus and sulfur mineralization in soil, respectively. Dust samples generated from a loam and sandy clay loam showed higher enzyme activities compared with dust samples from a fine sandy loam. Enzyme activities of dust samples were significantly correlated to the activities of the soil source with r > 0.74 (P < 0.01). The arylsulfatase proteins contents of the soils (0.04-0.65 mg protein kg(-1) soil) were lower than values reported for soils from other regions, but still dust contained arylsulfatase protein. The three enzyme activities studied, as a group, separated the dust samples due to the crop rotation or tillage practice history of the soil source. The results indicated that the enzyme activities of dust will aid in providing better characterization of dust properties and expanding our understanding of soil and air quality impacts related to wind erosion.
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PMID:Enzyme activities and arylsulfatase protein content of dust and the soil source: biochemical fingerprints? 1535 25

Sugar analogs were used to study the inhibition of cell wall-associated glycosidases in vitro and in vivo. For in vitro characterization, cell walls were highly purified from corn (Zea mays L.) root cortical cells and methods were developed to assay enzyme activity in situ. Inhibitor dependence curves, mode of inhibition, and specificity were determined for three sugar analogs. At low concentrations of castanospermine (CAS), 2-acetamido-1,5-imino-1,2,5-trideoxy-d-glucitol, and swainsonine, these inhibitors showed competitive inhibition kinetics with beta-glucosidase, beta-GIcNAcase, and alpha-mannosidase, respectively. Swainsonine specifically inhibited alpha-mannosidase activity, and 2-acetamido-1,5-imino-1,2,5-trideoxy-d-glucitol specifically inhibited beta-N-acetyl-hexosamindase activity. However, CAS inhibited a broad spectrum of cell wall-associated enzymes. When the sugar analogs were applied to 2 day old corn seedlings, only CAS caused considerable changes in root growth and development. To ensure that the concentration of inhibitors used in vitro also inhibited enzyme activity in vivo, an in vivo method for measuring cell wall-associated activity was devised.
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PMID:Inhibition of cell wall-associated enzymes in vitro and in vivo with sugar analogs. 1666 91

Sugar cane bagasse consists of hemicellulose (24%) and cellulose (38%), and bioconversion of both fractions to ethanol should be considered for a viable process. We have evaluated the hydrolysis of pretreated bagasse with combinations of cellulase, beta-glucosidase, and hemicellulase. Ground bagasse was pretreated either by the AFEX process (2NH(3): 1 biomass, 100 degrees C, 30 min) or with NH(4)OH (0.5 g NH(4)OH of a 28% [v/v] per gram dry biomass; 160 degrees C, 60 min), and composition analysis showed that the glucan and xylan fractions remained largely intact. The enzyme activities of four commercial xylanase preparations and supernatants of four laboratory-grown fungi were determined and evaluated for their ability to boost xylan hydrolysis when added to cellulase and beta-glucosidase (10 filter paper units [FPU]: 20 cellobiase units [CBU]/g glucan). At 1% glucan loading, the commercial enzyme preparations (added at 10% or 50% levels of total protein in the enzyme preparations) boosted xylan and glucan hydrolysis in both pretreated bagasse samples. Xylanase addition at 10% protein level also improved hydrolysis of xylan and glucan fractions up to 10% glucan loading (28% solids loading). Significant xylanase activity in enzyme cocktails appears to be required for improving hydrolysis of both glucan and xylan fractions of ammonia pretreated sugar cane bagasse.
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PMID:Hydrolysis of ammonia-pretreated sugar cane bagasse with cellulase, beta-glucosidase, and hemicellulase preparations. 1842 95

Comparative data is presented on glucose and xylose release for enzymatic hydrolysis of solids produced by pretreatment of poplar wood by ammonia fiber expansion (AFEX), ammonia recycled percolation (ARP), controlled pH, dilute acid, flowthrough (FT), lime, and sulfur dioxide (SO(2)) technologies. Sugar solubilization was measured for times of up to 72 h using cellulase supplemented with beta-glucosidase at an activity ratio of 1:2, respectively, at combined protein mass loadings of 5.8-116 mg/g of glucan in poplar wood prior to pretreatment. In addition, the enzyme cocktail was augmented with up to 11.0 g of xylanase protein per gram of cellulase protein at combined cellulase and beta-glucosidase mass loadings of 14.5 and 29.0 mg protein (about 7.5 and 15 FPU, respectively)/g of original potential glucose to evaluate cellulase-xylanase interactions. All pretreated poplar solids required high protein loadings to realize good sugar yields via enzymatic hydrolysis, and performance tended to be better for low pH pretreatments by dilute sulfuric acid and sulfur dioxide, possibly due to higher xylose removal. Glucose release increased nearly linearly with residual xylose removal by enzymes for all pretreatments, xylanase leverage on glucan removal decreased at high cellulase loadings. Washing the solids improved digestion for all pretreatments and was particularly beneficial for controlled pH pretreatment. Furthermore, incubation of pretreated solids with BSA, Tween 20, or PEG6000 prior to adding enzymes enhanced yields, but the effectiveness of these additives varied with the type of pretreatment.
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PMID:Effects of cellulase and xylanase enzymes on the deconstruction of solids from pretreatment of poplar by leading technologies. 1930 Dec 43