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)

A polygalacturonase was isolated from the culture medium of Sclerotinia borealis, a psychrophilic fungus that grows on lawn and wheat seedling under the snow in winter and induces the snow mold disease. Pectic acid was a better substrate of this enzyme than pectin when the activity was determined by measuring the reducing sugar produced. However, when the activity was measured by viscosity change, the viscosity of pectin decreased more rapidly than that of pectic acid. The results of viscosity change apparently indicate that the polygalacturonase catalyzes pectin hydrolysis as an endo-type enzyme. Highly methyl-esterified pectin was a poor substrate, as determined by measurements of reducing sugar production and viscosity change. It is suggested from the results that the methoxy group of pectin affects the polygalacturonase reaction. A reaction mechanism was proposed for the polygalacturonase reaction. Molecular mass of this enzyme was 40 kDa and its isoelectric point was pH 7.5. Optimum pH of the enzyme reaction was 4.5 and its optimum temperature was 40-50 degrees C. Thirty percent of the maximum activity was observed at 5 degrees C, but it was only slightly active above 60 degrees C. The activity was preserved for more than 2 years at 5 degrees C and pH 4.5, but it was lost when kept at room temperature overnight or heated at 50 degrees C for 30 min. The amino acid sequence of the N-terminal region of the psychrophilic polygalacturonase of Sclerotinia borealis is compared with those of polygalacturonases of mesophilic fungi. The function of this enzyme against the target plants is discussed with reference to the reaction of polygalacturonases of mesophilic fungi.
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PMID:Polygalacturonase isolated from the culture of the psychrophilic fungus Sclerotinia borealis. 916

Scanning electron microscopy (SEM) and chemical analysis were used to observe the cell wall changes that occur in cork with "mancha amarela", when compared to a standard cork. To mimic the microbial attack exhibited in cork with mancha amarela, the standard cork was treated enzymatically with commercial pectinase and hemicellulase preparations. The tissues treated with pectinase were comparable with those attacked with mancha amarela. Both were composed by deformed and wrinkly cells and exhibited cell wall separation at the middle lamella level, which suggests solubilization/removal of the pectic polysaccharides. The cork cell wall material, prepared as alcohol-insoluble residue, was fractionated by hot water (Pect(H)()2(O)) and hot dilute acid (Pect(acid)). The relatively large amount of hexuronic acid and the occurrence of Ara in the SPect(H)()2(O) and SPect(acid) allow to confirm, as far as we know, for the first time the presence of pectic polysaccharides in the cell walls of cork from Quercus suber L. They accounted for ca. 1.5% of the cork and may consist of polymers with long side chains of arabinosyl residues. These polymers have to be taken into account in any realistic model of the cork cell wall. Cork with mancha amarela contained a smaller amount of pectic polysaccharides (ca. 0.5%), which confirms that the cellular separation observed by SEM is related to the degradation/removal of the middle lamella pectic polysaccharides.
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PMID:Demonstration of pectic polysaccharides in cork cell wall from Quercus suber L. 1088 89