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:3.2.1.15 (pectinase)
2,440 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alcohol insoluble solids from apple were extracted in sequence by buffer at 20 degrees C and at 70 degrees C, EDTA/oxalate, and mild alkali, yielding four populations of pectins. These pectins and the insoluble residue were characterized by their sugar composition, degree of esterification (methyl ester and O-acetyl groups), molecular weight distribution, and degradability by the combination of endopolygalacturonase (PG) and pectin esterase (PE) and by rhamnogalacturonase (RGase) after chemical saponification. After PG/PE treatment, the remaining high molecular weight material representing the pectic hairy regions was isolated and characterized. Clear differences were found in the sugar composition of the fractions obtained, while only small variations were observed in the sugar linkage composition. The pectic hairy regions were further degraded by RGase and the digests separated into high molecular weight and oligomeric degradation products. These "RGase oligomers" consisted of between 4 and 9 sugar units with a backbone of alternating rhamnose and galacturonic acid residues, partly substituted with galactose linked to C-4 of the rhamnose moiety. Both the absolute amount of RGase oligosaccharides released as well as the degree of galactose-substitution of the oligomers increased when severer extraction conditions were used. Relatively more RGase oligomers were released from the low molecular weight hairy regions as compared to the high molecular weight fraction. Typical high molecular weight fragments isolated from the RGase digests of various hairy regions included residual segments of the rhamnogalacturonan backbone rich in arabinose and a polymer presumably enriched in xylogalacturonan segments.
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PMID:Different populations of pectic hairy regions occur in apple cell walls. 852 28

Orange peel, an abundant byproduct of the citrus processing industry, is converted to a mixture of glucose, galacturonic acid, fructose, arabinose, galactose, and xylose by hydrolysis with mixed pectinase and cellulase enzymes. All these sugars can be fermented to ethanol or ethanol and acetic acid by the recombinant bacterium Escherichia coli KO11. The fermentation efficiency is improved by the addition of yeast extract, tryptone, mixed amino acids, corn steep liquor, or by proteolytic digestion of endogenous proteins. Batch fermentations of supplemented peel hydrolysate containing 111 g/L of initial total sugars produced 35-38 g/L of ethanol in 48-72 h and a 75-85% yield.
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PMID:Fermentation of orange peel hydrolysates by ethanologenic Escherichia coli. Effects of nutritional supplements. 866 5

Aspergillus niger cinnamoyl esterase (CinnAE) is shown to be active towards a wide range of feruloylated oligosaccharides derived from sugar-beet pulp (SBP). The esterase hydrolysed ferulic acid ester-linked to either C-2 of arabinose or C-6 of galactose residues, and demonstrated the highest activity towards the feruloylated arabinose trisaccharide. However, CinnAE was able to release only 0.88% of total alkali-extractable ferulic acid from SBP in 24 h when acting alone. To determine whether cell-wall-degrading enzymes could increase the release of ferulic acid by CinnAE, SBP was incubated with various carbohydrases [cellulase, polygalacturonase, endo-arabinanase, alpha-L-arabinofuranosidase, endo-(1,4-beta-D-galactanase, beta-D-galactosidase]. These were added alone and in pairs, both in the presence and absence of CinnAE. We showed that all the carbohydrases tested were free of esterase activity. When individual carbohydrases were incubated with SBP, whether in the presence or absence of CinnAE, less than 1% of the feruloyl groups were released. When incubated with a mixture of endo-arabinanase and alpha-L-arabinofuranosidase, the esterase was able to release 14 times more of the alkali-extractable ferulic acid present in the whole pulp as free acid than CinnAE alone. Ferulic acid is linked either to L-arabinose or D-galactose in SBP, but no corresponding increase in ferulic acid release was detected when SBP was incubated with CinnAE plus endo-(1,4)-beta-D-galactanase and beta-D-galactosidase (both from A. niger). Hence feruloylated arabinans in SBP are readily available for hydrolysis by arabinan-degrading enzymes, whereas feruloylated galactans are not available for hydrolysis by galactan-degrading enzymes.
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PMID:Release of ferulic acid from sugar-beet pulp by using arabinanase, arabinofuranosidase and an esterase from Aspergillus niger. 867 11

The hot acid extract of pea hull, HSP, was rich in galacturonic acid, arabinose and xylose. It was fractionated by copper precipitation followed by ion-exchange chromatography. The copper-soluble fraction represented 26% of HSP and was mostly composed of an arabinan with a low degree of branching, some heteroxylans and a glucan, probably starch. The copper-precipitate (74% of HSP) contained pectins and some residual arabinan, xylan, glucan and mannan. One of the pectic fractions was rich in terminal xylose and fucose; it could be partially degraded by endo-polygalacturonase but not by endo-xylanase and seemed to contain xylogalacturonans.
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PMID:The xylose-rich pectins from pea hulls. 928 30

Commercial citrus pectin containing galacturonic acid and rhamnose in a ratio of approximately 40:1 was saponified and then exhaustively digested with endopolygalacturonase (EPG). The products were separated by ultrafiltration into low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions. The LMW fraction accounted for 80% of the starting material, but for only 10% of the total rhamnose. The molar ratio of galacturonic acid to rhamnose of the LMW fraction was 236, suggesting that very few small Rha-containing oligomers were generated by the EPG digestion. No distinct Rha-containing oligomers were found by various chromatographic analyses of the LMW fraction. The HMW fraction, which only accounted for 10% by weight of the starting pectin, contained more than 85% of the rhamnose. The ratio of GalA to Rha in the HMW fraction was 1.7:1 and partial acid hydrolysis of this fraction produced a series of oligomers consisting of GalA-Rha repeating units, suggesting that it contained rhamnogalacturonan, which has a backbone composed of GalA-Rha disaccharide repeating units. The HMW fraction also contained large amounts of arabinose and galactose, which probably originated from side chains linked to some of the rhamnose residues. We propose that commercial citrus pectin is composed of two regions: the predominant region consists of chains of uninterrupted 1,4-linked alpha-D-GalA residues with between 60-70% of the residues methyl esterified; and the other region consists of rhamnogalacturonan with a backbone composed of GalA-Rha disaccharide repeating units and neutral sugar side chains.
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PMID:Scarcity or complete lack of single rhamnose residues interspersed within the homogalacturonan regions of citrus pectin. 971 29

Apple-pectin hairy regions were prepared from apple pectin by combined action of the recombinant Aspergillus niger enzymes endopolygalacturonase II and pectin methylesterase and the A. tubigensis exopolygalacturonase. Using this enzymically prepared pectin fraction, an additional activity of the A. tubigensis exopolygalacturonase was discovered only when the substrate was chemically saponified and when D-galacturonate, a potent inhibitor of the enzyme, was removed from the incubation mixture. The new reaction product was purified and could be hydrolysed by A. niger beta-xylosidase into D-galacturonate and beta-D-xylose in a 1:1 ratio, which identified it as xylogalacturonate. The results demonstrate that exopolygalacturonase is not only active on galacturonan but also on xylogalacturonan. The enzyme thus accomodates a substrate in which the terminal galacturonic acid residue carries a single xylose substitution. The well-defined substrate specificity of exopolygalacturonase opens the possibility for use of this enzyme in biotechnological applications, such as preparing pectins that are methylated at the non-reducing end, and for studying the fine structure of xylogalacturonan in pectin.
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PMID:The exopolygalacturonase from Aspergillus tubingensis is also active on xylogalacturonan. 1046 19

The production of cell wall-degrading enzymes (wall depolymerases) by plant pathogenic fungi is under catabolite (glucose) repression. In Saccharomyces cerevisiae, the SNF1 gene is required for expression of catabolite-repressed genes when glucose is limiting. An ortholog of SNF1, ccSNF1, was isolated from the maize pathogen Cochliobolus carbonum, and ccsnf1 mutants of HC toxin-producing (Tox2(+)) and HC toxin-nonproducing (Tox2(-)) strains were created by targeted gene replacement. Growth in vitro of the ccsnf1 mutants was reduced by 50 to 95% on complex carbon sources such as xylan, pectin, or purified maize cell walls. Growth on simple sugars was affected, depending on the sugar. Whereas growth on glucose, fructose, or sucrose was normal, growth on galactose, galacturonic acid, maltose, or xylose was somewhat reduced, and growth on arabinose was strongly reduced. Production of HC toxin was normal in the Tox2(+) ccsnf1 mutant, as were conidiation, conidial morphology, conidial germination, and in vitro appressorium formation. Activities of secreted beta-1,3-glucanase, pectinase, and xylanase in culture filtrates of the Tox2(+) ccsnf1 mutant were reduced by 53, 24, and 65%, respectively. mRNA expression was downregulated under conditions that induced the following genes encoding secreted wall-degrading enzymes: XYL1, XYL2, XYL3, XYL4, XYP1, ARF1, MLG1, EXG1, PGN1, and PGX1. The Tox2(+) ccsnf1 mutant was much less virulent on susceptible maize, forming fewer spreading lesions; however, the morphology of the lesions was unchanged. The Tox2(-) ccsnf1 mutant also formed fewer nonspreading lesions, which also retained their normal morphology. The results indicate that ccSNF1 is required for biochemical processes important in pathogenesis by C. carbonum and suggest that penetration is the single most important step at which ccSNF1 is required. The specific biochemical processes controlled by ccSNF1 probably include, but are not necessarily restricted to, the ability to degrade polymers of the plant cell wall and to take up and metabolize the sugars produced.
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PMID:The Cochliobolus carbonum SNF1 gene is required for cell wall-degrading enzyme expression and virulence on maize. 1066 60

The filamentous fungus Penicillium olsonii secretes several polygalacturonases (PGs) with molecular masses of about 47 kDa. These enzymes consist of several basic and acidic isoforms, with dominant activities at pI 4.5 and pI 7.9. Two polygalacturonase genes, pg1 and pg2, have been cloned. The corresponding enzymes, PG1 and PG2, consist of 370 and 380 amino acids, respectively, and show significant similarities to endo-polygalacturonases from other filamentous fungi. Targeted disruption of pg1 resulted in the elimination of all basic PG isoforms. In contrast, disruption of pg2 reduced, but did not eliminate the acidic PG activities. The PGs of P. olsonii must therefore be encoded by a gene family of at least three genes. Induction studies with various carbon sources revealed that the acidic and basic isoforms are differentially regulated. Pectin is the best inducer of the acidic PG isoforms. The basic isoforms, however, are best induced by monosaccharides like glucose, alpha-L-rhamnose and alpha-L-arabinose.
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PMID:Cloning and targeted disruption of two polygalacturonase genes in Penicillium olsonii. 1080 87

Water-soluble polysaccharide fractions VO1-VO4 were isolated from the squeezed berries of snowball tree (Viburnum opulus) by successive extraction with water at various temperatures and pH and with aqueous solutions of ammonium oxalate. These fractions were purified by ion-exchange chromatography on DEAE cellulose, and the homogeneity of the purified polysaccharides was determined by gel filtration on Sephacryl S-500. Acidic polysaccharides close to pectins in their sugar composition were found in all the extracts (fractions VO1-1, VO2-1, VO3-2, and VO4-2). Residues of galacturonic acid, galactose, arabinose, and (to a lesser extent) rhamnose are their main constituents. Neutral polysaccharides composed mainly of galactose and mannose residues were additionally found in fractions extracted with acidified water (pH 4.0) and with aqueous ammonium oxalate solutions. Partial acidic hydrolysis and digestion with pectinase of acidic polysaccharides indicated that their carbohydrate backbone consists of alpha-1,4-linked residues of D-galacturonic acid. NMR spectra of acidic polysaccharides (fractions VO3-2 and VO3-3) confirmed this and demonstrated that their side oligosaccharide chains are composed of beta-1,4-linked galactopyranose residues and of terminal and 2,5- and 3,5-substituted residues of alpha-arabinofuranose at a Gal: Ara ratio of 3:1. Some polysaccharides from V. opulus were found to possess an immunostimulating activity: they enhance phagocytosis, in particular, the phagocytic index and the secretion of lysosomal enzymes with peritoneal macrophages. Calcium ions were found to be necessary for the appearance of the stimulating effect of acidic polysaccharides from V. opulus.
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PMID:[The isolation, preliminary study of structure and physiological activity of water-soluble polysaccharides from squeezed berries of Snowball tree Viburnum opulus]. 1080 53

Polysaccharides from the roots of Panax ginseng were extracted by hot water and fractionated by using ethanol precipitation and ion exchange chromatography. Fractions FC (crude extract), F1 (fraction precipitated by ethanol), F1N (fraction unbound to DEAE-Sepharose CL-6B), and F1A (bound fraction) were obtained. Their carbohydrate analyses showed that acidic fraction F1A contains higher amounts of galactose, arabinose and uronic acids, in comparison to FC and F1. Fraction F1N mainly consists of glucose. The inhibition of Helicobacter pylori-induced hemagglutination revealed different inhibitory activities of these fractions. In particular, acidic fraction F1A showed a remarkable inhibitory activity (minimum inhibition concentration was 0.25 mg/ml) among the polysacharide fractions. However, digestion of the fraction F1A with pectinase resulted in a lower molecular weight oligosaccharide fraction F1AP which was non-inhibitory at the concentration of 4 mg/ml. Comparison of inhibitory activities and carbohydrate compositions of isolated fractions indicates that the activity correlated with the contents of galactose, arabinose, and uronic acids. These data suggest that acidic polysaccharides may be responsible for the inhibitory activity.
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PMID:Inhibition of Helicobacter pylori hemagglutination by polysaccharide fractions from roots of Panax ginseng. 1082 Oct 45


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