Linked Life Data

11359613

Source:http://linkedlifedata.com/resource/pubmed/id/11359613

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-5-21
pubmed:abstractText
Disproportionating enzyme (D-enzyme) is a plastidial alpha-1,4-glucanotransferase but its role in starch metabolism is unclear. Using a reverse genetics approach we have isolated a mutant of Arabidopsis thaliana in which the gene encoding this enzyme (DPE1) is disrupted by a T-DNA insertion. While D-enzyme activity is eliminated in the homozygous dpe1-1 mutant, changes in activities of other enzymes of starch metabolism are relatively small. During the diurnal cycle, the amount of leaf starch is higher in dpe1-1 than in wild type and the amylose to amylopectin ratio is increased, but amylopectin structure is unaltered. The amounts of starch synthesised and degraded are lower in dpe1-1 than in wild type. However, the lower amount of starch synthesised and the higher proportion of amylose are both eliminated when plants are completely de-starched by a period of prolonged darkness prior to the light period. During starch degradation, a large accumulation of malto-oligosaccharides occurs in dpe1-1 but not in wild type. These data show that D-enzyme is required for malto-oligosaccharide metabolism during starch degradation. The slower rate of starch degradation in dpe1-1 suggests that malto-oligosaccharides affect an enzyme that attacks the starch granule, or that D-enzyme itself can act directly on starch. The effects on starch synthesis and composition in dpe1-1 under normal diurnal conditions are probably a consequence of metabolism at the start of the light period, of the high levels of malto-oligosaccharides generated during the dark period. We conclude that the primary function of D-enzyme is in starch degradation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
89-100
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
A critical role for disproportionating enzyme in starch breakdown is revealed by a knock-out mutation in Arabidopsis.
pubmed:affiliation
Institute of Cell and Molecular Biology, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JH, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't