Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.2.10 (PNL)
 341 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The production of pectinase was studied in Neurospora crassa, using the hyperproducer mutant exo-1, which synthesized and secreted five to six times more enzyme than the wild-type. Polygalacturonase, pectin lyase and pectate lyase were induced by pectin, and this induction was glucose-repressible. Polygalacturonase was induced by galactose four times more efficiently than by pectin; in contrast the activity of lyases was not affected by galactose. The inducing effect of galactose on polygalacturonase was not glucose-repressible. Extracellular pectinases were separated by ion exchange chromatography. Pectate and pectin lyases eluted into three main fractions containing both activities; polygalacturonase eluted as a single, symmetrical peak, apparently free of other protein contaminants, and was purified 56-fold. The purified polygalacturonase was a monomeric glycoprotein (38% carbohydrate content) of apparent molecular mass 36.6-37.0 kDa (Sephadex G-100 and urea-SDS-PAGE, respectively). The enzyme hydrolysed predominantly polypectate. Pectin was also hydrolysed, but at 7% of the rate for polypectate. Km and Vmax for polypectate hydrolysis were 5.0 mg ml-1 and 357 mumol min-1 (mg protein)-1, respectively. Temperature and pH optima were 45 degrees C and 6.0, respectively. The purified polygalacturonase reduced the viscosity of a sodium polypectate solution by 50% with an increase of 7% in reducing sugar groups. The products of hydrolysis at initial reaction times consisted of oligogalacturonates without detectable monomer. Thus, the purified Neurospora crassa enzyme was classified as an endopolygalacturonase [poly(1,4-alpha-D-galacturonide) glycanohydrolase; EC 3.2.1.15].
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PMID:Pectinase production by Neurospora crassa: purification and biochemical characterization of extracellular polygalacturonase activity. 183 96

Endo-pectin lyase and endo-polygalacturonase of Aspergillus japonicus attack the middle lamella of plant tissue and cause tissue maceration. Galacturonides, neutral sugars, and proteins were released from potato tuber tissues during maceration by both purified enzymes. These three components accounted for 92% of the soluble products. The neutral sugars released were rhamnose, arabinose, and galactose with a molar ratio of 1:3:15. They were covalently linked to galacturonides. Over 85% of the galacturonides released by the enzymes were short chain products, which indicated that a large portion of the main chain of pectic substances is a homogalacturonan. The results of chromatography on columns of Sephadex G-100 and DEAE-cellulose suggested that a protein component may be attached to pectic substances. This protein did not contain hydroxyproline and, therefore, was different from the cell wall structural glycoprotein.
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PMID:Analysis of the Components Released from Potato Tuber Tissues during Maceration by Pectolytic Enzymes. 1666 May 64