Linked Life Data

1835496

Source:http://linkedlifedata.com/resource/pubmed/id/1835496

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1991-12-30
pubmed:abstractText
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].
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-1287
pubmed:author
pubmed:issnType
Print
pubmed:volume
137
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1815-23
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Pectinase production by Neurospora crassa: purification and biochemical characterization of extracellular polygalacturonase activity.
pubmed:affiliation
Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't