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)

Five strains of gram-negative, yellow chromogenic bacilli were recovered from clinical specimens which fit the characteristics of the "lathyri-herbicola group" within the genus Erwinia. The strains were facultatively anaerobic, fermentative, anaerogenic bacilli with peritrichous flagella which grew at 37 C, reduced nitrate to nitrite, and failed to produce oxidase, pectinase, arginine dihydrolase, and decarboxylases for lysine and ornithine. Aggregations of bacteria (symplasmata) were observed in the syneresis water of slant cultures, and analogous granular aggregates and biconvex, spindle-shaped bodies developed in colonies on plate cultures. Awareness of these characteristics should result in more frequent identification of Erwinia species from human sources.
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PMID:Unusual fermentative, gram-negative bacilli isolated from clinical specimens. I. Characterization of Erwinia strains of the "lathyri-herbicola group". 545 36

Chemical composition and physicochemical properties of an immunomodulator, which is a non-dialyzable and acetone precipitable material(s) extracted with hot water from Angelica actiloba KITAGAWA (Yamato Tohki) (AIP), were investigated. AIP was composed of about 90% sugar and 10% protein. The major polysaccharide was identified as pectic substance(s) because its main component sugars were found to be arabinose, glucose, and galacturonic acid by gas liquid chromatographic analysis. The pectic substance(s) was not concerned with the mitogenicity of AIP since the activity was similar before and after pectinase(endo-polygalacturonase) treatment. More than half of the mitogenicity was destroyed by acid or alkali treatment. With pronase treatment, the activity was not affected, but the molecular weight of the mitogen was lowered. In addition, the mitogenic substance was partially purified from AIP by pectinase treatment and Westphal's phenol/water fractionation. The partially purified mitogenic substance(s) was rich in protein. These facts suggest that the mitogenicity of AIP was carried by a heat stable and protease resistant protein.
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PMID:Biochemical and physicochemical characterization of a mitogen obtained from an oriental crude drug, Tohki (Angelica actiloba Kitagawa). 667 76

Scale tissues taken from cones of pendent Douglas-fir Pseudotsuga menziesii (Mirb.) Franco were treated with pectinase to dissociate nuclei for Feulgen staining. Hydration of fixed tissues with water or a graded series of ethyl alcohol before pectinase treatment resulted in distention and faint staining of nuclei and inadequate disintegration of cell walls. These problems were overcome by adopting citrate buffer hydration. Analysis of digitized scans of nuclei provided information about the distribution of the stained material in density classes and nuclear size which is usually unavailable through the conventional double wavelength DNA measuring method.
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PMID:Use of pectinase to dissociate plant nuclei for squash preparations: effect of hydration procedures. 675 7

Bupleuri Radix is a commonly used medicinal plant in Kampo medicine, and its hot water extracts show mitogenic activity to murine lymphocytes. In this paper the mitogenic substances in the hot water extracts of Bupleuri Radix (Bup-HWE) were fractionated and characterized physicochemically and immunologically. Most of these substances were recovered from mol. wt of more than 200 kDA fraction (fr. C-13). Separation of fr. C-13 by phenol-water fractionation method gave water soluble and phenol soluble mitogenic substances. These substances showed the activity even in C3H/HeJ mice, and polymyxin B or lysozyme treatment did not abrogate the activity, suggesting that the active substances are not related to bacterial lipopolysaccharide. Treatment of the mitogenic substances recovered from the phenol layer with NaCLO2, a polyphenol degrading chemical, significantly reduced the activity, but pronase and pectinase treatments were not effective. The mitogenic substances in the water layer were active even after NaCLO2 treatment. These findings suggested that the mitogenic substances of Bup-HWE are large molecular weight polyphenolic compounds and polysaccharide. The mitogenic substances are suggested to be B cell mitogens.
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PMID:Characterization of mitogenic substances in the hot water extracts of bupleuri radix. 749 96

The characteristic features of the pectins present in the walls of immature fibre cells of the hypocotyl of flax seedlings have been studied by a combination of three subtractive methods (treatment with boiling water, calcium chelator, and free endopolygalacturonase), three staining reactions (periodic acid-thiocarbohydrazide-silver, Ruthenium Red, and ferric hydroxylamine) and labelling with an endopolygalacturonase-gold probe. The primary wall and the periphery of the tricellular junctions were shown to contain pectic molecules made of blocks either with free acidic functions or methyl-esterified, these molecules being removed from the wall by splitting alpha (1-4) linkages. On the contrary, the pectic molecules in the core of the tricellular junctions were mainly with free acidic groups, but with an appreciable acetylesterification of their hydroxyl groups; and they were linked with one another chiefly by calcium bonds. This unexpected constitution of the core of the tricellular junctions may be considered to be an early marker of the cells destined to give rise to the fibre bundles of the mature plant.
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PMID:Polysaccharide distribution in the cellular junctions of immature fibre cells of flax seedlings. 751 66

Fluorescent measurement of the carboxyl group was achieved using water-soluble carbodiimide, EDC (1-ethyl-3-(3- dimethylaminopropyl)carbodiimide). Detection of the active intermediate from the glucuronic acid-EDC reaction mixture using the OPA (o-phthalaldehyde) reagent described in a previous paper was greatly improved to about 4 ng/tube (17 pmol) glucuronic acid owing to a modification of the OPA cocktail. Moreover, fluorescent EDAN (N-1-ethylenediamino-naphthalene) labeling of the carboxyl group was also enabled by EDC catalysis. Quenching of the excess fluorescence of EDAN by OPA increased the sensitivity of EDC-EDAN to a level above the EDC-OPA method. In addition to the assay of enzymes concerning the uronic acid metabolism such as pectinase and pectinesterase, lipase and protease actions could be measured by the EDC-OPA and EDC-EDAN quenching methods, respectively. Thus, these two fluorescent means of detecting carboxyl groups seemed to have extensive application not only to acidic sugars but also to various carboxylic compounds regardless of their solubility.
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PMID:Water-soluble carbodiimide for the fluorescent measurement of the carboxyl group produced by enzyme reactions. 808 75

Erwinia carotovora subsp. carotovora wild-type strain Ecc71 does not elicit the hypersensitive reaction (HR) in tobacco leaves. By mini-Tn5-Km and chemical mutagenesis we have isolated RsmA- mutants of Ecc71 that produce high basal levels of pectate lyases, polygalacturonase, cellulase, and protease; they also are hypervirulent. The RsmA- mutants, but not their parent strains, elicit an HR-like response in tobacco leaves. This reaction is characterized by the rapid appearance of water soaking followed by tissue collapse and necrosis. The affected areas remain limited to the region infiltrated with bacterial cells, and the symptoms closely resemble a typical HR, e.g., the reactions caused by Pseudomonas syringae pv. pisi. Moreover, low concentrations of cells of the mini-Tn5-Km insertion RsmA- mutant, AC5070, infiltrated into tobacco leaf tissue prevent elicitation of the rapid necrosis by AC5070 or by P. syringae pv. pisi. Elicitation of the HR-like response by the mutants is not affected by the deficiency of N-(3-oxohexanoyl)-L-homoserine lactone, the cell density (quorum) sensing signal. Cloning and sequence analysis have disclosed that E. carotovora subsp. carotovora strain Ecc71 possesses a homolog of E. chrysanthemi hrpN known to encode an elicitor of the HR; the corresponding Ecc71 gene is designated hrpNEcc. Northern (RNA) blot data show that the level of hrpNEcc mRNA is considerably higher in the RsmA- mutants than in the RsmA+ strains. Moreover, a low copy plasmid carrying the rsmA+ allele severely reduces the level of the hrpNEcc transcripts in the RsmA- mutants. These constructs, like the RsmA+ E. carotovora subsp. carotovora strains, do not elicit the HR-like response. These data taken along with the effects of rsmA on exoenzyme production and pathogenicity (A. Chatterjee et al., 1995, Appl. Environ. Microbiol. 61:1959-1967) demonstrate that this global regulator gene plays a critical role in plant interaction of E. carotovora subsp. carotovora.
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PMID:The RsmA- mutants of Erwinia carotovora subsp. carotovora strain Ecc71 overexpress hrpNEcc and elicit a hypersensitive reaction-like response in tobacco leaves. 881 71

The mechanism of action for the hydrolysis of polygalacturonic acid by the enzyme endo-polygalacturonase (poly(1,4-alpha-D-galacturonide) glycanohydrolase, EC 3.2.1.15) was investigated. The enzyme from Aspergillus ustus was purified to homogeneity and used for the study. The endo-polygalacturonase had a molecular weight of 36,000 daltons, a pI of 8.3, specific activity of 785 units/mg, Km of 0.82 mg/ml, and Vmax of 976 micromoles of product min-1 mg-1. Amino acids involved in the catalysis were identified by chemical modification and the active site characterized. Inhibition by hydroxynitrobenzyl bromide and diethylpyrocarbonate, followed by substrate protection studies showed that tryptophan and histidine were involved at or near the active site. Kinetic constants of partially inhibited enzyme, suggest the involvement of tryptophan in substrate binding and histidine in catalysis. Quenching of tryptophan fluorescence of the enzyme in the presence of polygalacturonic acid substantiated the conclusion that tryptophan was involved in substrate binding. An isotope effect of 1.8 was observed with deuterated water on the Vmax of the endo-polygalacturonase, with the proton inventory giving a linear relationship. The proposed mechanism involves a single proton transfer from the histidine residue of the enzyme to the glycosidic oxygen and hydrolysis by the addition of a water molecule.
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PMID:Implication of tryptophan and histidine in the active site of endo-polygalacturonase from Aspergillus ustus: elucidation of the reaction mechanism. 881 23

The transfer of a methyl group from S-adenosyl-L-methionine onto the carboxyl group of alpha-1,4-linked-galactosyluronic acid residues in the pectic polysaccharide homogalacturonan (HGA) is catalyzed by an enzyme commonly referred to as pectin methyltransferase. A pectin methyltransferase from microsomal membranes of tobacco (Nicotiana tabacum) was previously characterized (F. Goubet, L.N. Council, D. Mohnen [1998] Plant Physiol 116: 337-347) and named HGA methyltransferase (HGA-MT). We report the solubilization of HGA-MT from tobacco membranes. Approximately 22% of the HGA-MT activity in total membranes was solubilized by 0.65% (w/v) 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid containing 1 mM dithioerythritol. The addition of phosphatidylcholine and the methyl acceptors HGA or pectin (30% degree of esterification) to solubilized enzyme increased HGA-MT activity to 35% of total membrane-bound HGA-MT activity. Solubilized HGA-MT has a pH optimum of 7.8, an apparent K(m) for S-adenosyl-L-methionine of 18 microM, and an apparent V(max) of 0. 121 pkat mg(-1) of protein. The apparent K(m) for HGA and for pectin is 0.1 to 0.2 mg mL(-1). Methylated product was solubilized with boiling water and ammonium oxalate, two conditions used to solubilize pectin from the cell wall. The release of 75% to 90% of the radioactivity from the product pellet by mild base treatment showed that the methyl group was incorporated as a methyl ester rather than a methyl ether. The fragmentation of at least 55% to 70% of the radiolabeled product by endopolygalacturonase, and the loss of radioactivity from the product by treatment with pectin methylesterase, demonstrated that the bulk of the methylated product produced by the solubilized enzyme was pectin.
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PMID:Solubilization and partial characterization of homogalacturonan-methyltransferase from microsomal membranes of suspension-cultured tobacco cells. 1048 84

Polygalacturonases specifically hydrolyze polygalacturonate, a major constituent of plant cell wall pectin. To understand the catalytic mechanism and substrate and product specificity of these enzymes, we have solved the x-ray structure of endopolygalacturonase II of Aspergillus niger and we have carried out site-directed mutagenesis studies. The enzyme folds into a right-handed parallel beta-helix with 10 complete turns. The beta-helix is composed of four parallel beta-sheets, and has one very small alpha-helix near the N terminus, which shields the enzyme's hydrophobic core. Loop regions form a cleft on the exterior of the beta-helix. Site-directed mutagenesis of Asp(180), Asp(201), Asp(202), His(223), Arg(256), and Lys(258), which are located in this cleft, results in a severe reduction of activity, demonstrating that these residues are important for substrate binding and/or catalysis. The juxtaposition of the catalytic residues differs from that normally encountered in inverting glycosyl hydrolases. A comparison of the endopolygalacturonase II active site with that of the P22 tailspike rhamnosidase suggests that Asp(180) and Asp(202) activate the attacking nucleophilic water molecule, while Asp(201) protonates the glycosidic oxygen of the scissile bond.
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PMID:1.68-A crystal structure of endopolygalacturonase II from Aspergillus niger and identification of active site residues by site-directed mutagenesis. 1052 27


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