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)

An assay for cellulase activity based on the oxidation of cellobiose, formed during the cellulase reaction, with ferricyanide and a cellobiose dehydrogenase derived from the cellulolytic fungus Sporotrichum (Chrysosporium) thermophile is presented. Due to the restricted specificity of this enzyme for cellobiose and cellodextrins, glucose, which may be formed by the action of some cellulolytic components or by beta-glucosidase, does not contribute to the result. The negative interference of beta-glucosidase may be eliminated by glucono-delta-lactone inhibition. The assay, which is not influenced by cellobiose back-inhibition of the cellulase reaction, like the usual cellulase tests based on the increase in reducing power, is basically unspecific with respect to endo- or exo-acting enzymes giving rise to a total cellulase activity. With the use of an amorphous cellulose substrate (reprecipitated cellulose after dissolving in concentrated phosphoric acid), unpredictable effects due to cooperativity between endo- and exo-enzyme components were eliminated. An analytical procedure giving a linear response between activity and enzyme concentration and between activity and time of incubation has been worked out.
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PMID:A cellulase assay coupled to cellobiose dehydrogenase. 392 12

The enzyme cellobiose dehydrogenase (CDH), produced by many wood-degrading fungi has, in recent years, attracted considerable interest for its possible role in both cellulose and lignin degradation. To characterize the enzyme better and to identify its role in the degradation of wood and wood components, it is desirable to produce it in higher amounts. We report here that the addition of bovine calf serum to cellulose-grown cultures of Phanerochaete chrysosporium enhances the production of certain enzymes, CDH in particular. The highest CDH production was obtained with 45 ml of serum/litre of medium added on day 3 or 4. The resultant CDH yield was approx. 700-800 units/litre, which was 3.5-4 times higher than that in cultures without serum. Serum addition also enhanced the production of beta-glucosidase. However, the impact on CDH production was the most dramatic. The enhanced enzyme production cannot be explained by increased rates of spore germination, simple nutrient effects or cofactor effects. Fractionation of serum by Cohn's fractionation technique showed that the albumin (BSA) fraction had almost the same effect as whole serum. However, purified BSA had less effect than crude BSA (fraction V of Cohn's fractions), suggesting that an additional factor, probably a protease inhibitor in serum, also contributed to the effect of serum.
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PMID:Enhanced production of cellobiose dehydrogenase in cultures of Phanerochaete chrysosporium supplemented with bovine calf serum. 935 5

Transcriptional analysis of beta-glucosidase gene (bgl) and cellobiose dehydrogenase gene (cdh) in relation to cellobiose metabolism in the basidiomycete Phanerochaete chrysosporium was performed using real-time quantitative RT-PCR. Addition of glucose to cellulose-degrading culture significantly decreased the number of both transcripts. In contrast, addition of cellobiose repressed only transcription of bgl but no effect for that of cdh. Moreover, to investigate induction of the two genes, the mycelia grown on glucose medium were transferred to medium containing glucose, cellobiose or no carbon source. In cellobiose medium, the number of bgl transcripts was slightly lower, whereas that of cdh transcripts was 2.3-fold higher than those in glucose medium. Consequently, cellobiose represses transcription of bgl, whereas it induces that of cdh.
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PMID:Differential transcription of beta-glucosidase and cellobiose dehydrogenase genes in cellulose degradation by the basidiomycete Phanerochaete chrysosporium. 1515 79

Nonsporulating mycelial fungi producing cellobiose dehydrogenase (CDH) and isolated from soils of South Vietnam with high residual content of dioxins are capable of growing on a solid medium in the presence of high atrazine concentrations (to 500 mg/l). At 20 and 50 mg/l atrazine, the area of fungal colonies was 1.5-1.2-fold larger, respectively, compared with control colonies of the same age, whereas development of the colonies at 500 mg/l atrazine was delayed by 5 days, compared with controls grown in the absence of atrazine. Surface cultivation of the fungus on a minimal medium with glucose as a sole source of carbon and energy decreased the initial concentration of atrazine (20 mg/l) 50 times in 40 days; in addition, no pronounced sorption of atrazine by mycelium was detected. This was paralleled by accumulation in the culture medium of extracellular CDH; atrazine increased the synthesis of this enzyme two- to threefold. Accumulation of beta-glucosidase (a mycelium-associated enzyme) and cellulases preceded the formation of CDH.
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PMID:[Degradation of the herbicide atrazine by the soil mycelial fungus INBI 2-26(-)--a producer of cellobiose dehydrogenase]. 1528 38

The substrate specificity of an extracellular beta-glucosidase (BGL) from cellulose-degrading culture of the white-rot fungus Phanerochaete chrysosporium was investigated, using a variety of compounds with beta-glucosidic linkages. Amino acid sequencing data for the purified BGL showed that the enzyme is identical to the glycoside hydrolase (GH) family 3 BGL of the same fungus previously reported [Li, B. and Renganathan, V, Appl. Environ. Microbiol., 64, 2748-2754 (1998)]. The BGL can hydrolyze both cellobiose and cellobionolactone, but cellobionolactone was hydrolyzed very much more slowly than cellobiose. Moreover, cellobionolactone inhibited cellobiose hydrolysis by the BGL, suggesting that this enzyme cannot cooperate with cellobiose dehydrogenase (CDH) in cellulose degradation by P. chrysosporium. In addition to cellobiose, BGL utilized various glucosyl-beta-glucosides, such as sophorose, laminaribiose and gentiobiose, as substrates. Among the four substrates, laminaribiose (beta-1,3-glucosidic linkage) was hydrolyzed most effectively. Moreover, the hydrolytic rate of laminarioligosaccharides increased proportionally to the degree of polymerization (DP), and the activity of BGL even towards laminarin with an average DP of 25 was similar to that towards laminaripentaose (DP 5). Therefore, we conclude that the extracellular BGL from P. chrysosporium is primarily a glucan 1,3-beta-glucosidase (EC 3.2.1.58), which might play a role on fungal cell wall metabolism, rather than a beta-glucosidase (EC 3.2.1.21), which might be involved in the hydrolysis of beta-1,4-glucosidic compounds during cellulose degradation.
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PMID:Family 3 beta-glucosidase from cellulose-degrading culture of the white-rot fungus Phanerochaete chrysosporium is a glucan 1,3-beta-glucosidase. 1623 59

Cellulose is the main polymeric component of the plant cell wall, the most abundant polysaccharide on Earth, and an important renewable resource. Basidiomycetous fungi belong to its most potent degraders because many species grow on dead wood or litter, in environment rich in cellulose. Fungal cellulolytic systems differ from the complex cellulolytic systems of bacteria. For the degradation of cellulose, basidiomycetes utilize a set of hydrolytic enzymes typically composed of endoglucanase, cellobiohydrolase and beta-glucosidase. In some species, the absence of cellobiohydrolase is substituted by the production of processive endoglucanases combining the properties of both of these enzymes. In addition, systems producing hydroxyl radicals based on cellobiose dehydrogenase, quinone redox cycling or glycopeptide-based Fenton reaction are involved in the degradation of several plant cell wall components, including cellulose. The complete cellulolytic complex used by a single fungal species is typically composed of more than one of the above mechanisms that contribute to the utilization of cellulose as a source of carbon or energy or degrade it to ensure fast substrate colonization. The efficiency and regulation of cellulose degradation differs among wood-rotting, litter-decomposing, mycorrhizal or plant pathogenic fungi and yeasts due to the different roles of cellulose degradation in the physiology and ecology of the individual groups.
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PMID:Degradation of cellulose by basidiomycetous fungi. 1837 Nov 73

Production of cellulolytic enzymes, such as cellobiohydrolases (CBH) and cellobiose dehydrogenase (CDH), by the basidiomycete Phanerochaete chrysosporium is significantly repressed in glucose-containing media; this is known as carbon catabolite repression. We have analyzed the glucose concentration dependence of transcript numbers of the cellulolytic genes (cel6A, cel7D, and cdh) and beta-glucosidase gene (bgl3A) by means of real-time quantitative reverse transcriptase polymerase chain reaction to investigate the roll of carbon catabolite derepression in these gene expression. When the mycelium of P. chrysosporium grown in glucose culture was transferred to media containing various concentrations of glucose (0-5,000 microM), the expression levels of cel6A, cel7D, and cdh were drastically influenced by glucose, whereas no significant change was observed in bgl3A. The numbers of transcripts of cel6A, cel7D, and cdh increased exponentially during incubation for 6 h in the culture without glucose, and the rates of increase were 2.1 times per hour for cel6A transcripts and 2.7 times per hour for cel7D transcripts. Moreover, derepression of cel6A and cel7D was delayed (by 1.6 and 0.6 h, respectively) when the culture contained 50 microM glucose compared with that in the absence of glucose, suggesting that the promoter activities of cel7D and cel6A are distinct under conditions of carbon catabolite derepression.
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PMID:Real-time quantitative analysis of carbon catabolite derepression of cellulolytic genes expressed in the basidiomycete Phanerochaete chrysosporium. 1856 9