Linked Life Data

15375646

Source:http://linkedlifedata.com/resource/pubmed/id/15375646

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2004-10-19
pubmed:abstractText
In many bacteria, pyruvate kinase serves a well-defined function in glycolysis, catalyzing an ATP-generating reaction. However, its role during growth on carbon sources requiring glucoeneogenesis is less well investigated. We analyzed a defined pyruvate kinase gene (pyk) deletion mutant of Corynebacterium glutamicum, which is unable to grow on ribose as sole carbon source. Unexpectedly, the pyk deletion mutant was also unable to grow on acetate or citrate as sole carbon sources unless low amounts of pyruvate were added to the growth medium. A spontaneous suppressor mutant of the pyk deletion strain that regained the ability to grow on acetate was isolated. DNA microarray experiments revealed increased expression of the malic enzyme gene malE. The point mutation upstream of malE identified in this mutant was responsible for the loss of carbon-source-dependent regulation, as revealed by transcriptional fusion analysis. Overexpression of malE was sufficient to restore growth of the pyk deletion strain on acetate or citrate. The requirement of increased malic enzyme levels to re-route the carbon flux at the interface between glycolysis, gluconeogenesis and the tricarboxylic acid cycle in order to compensate for the absence of pyruvate kinase indicates a metabolic flux bifurcation at the metabolic node phosphoenolpyruvate. Whereas during growth of C. glutamicum on acetate or citrate most of the phosphoenolpyruvate generated from oxaloacetate is metabolized in gluconeogenesis, a fraction is converted by pyruvate kinase in the glycolytic direction to sustain proper pyruvate availability for biomass synthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0302-8933
pubmed:author
pubmed:issnType
Print
pubmed:volume
182
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
354-63
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Roles of pyruvate kinase and malic enzyme in Corynebacterium glutamicum for growth on carbon sources requiring gluconeogenesis.
pubmed:affiliation
Institute of Biotechnology 1, Research Centre Jülich, 52425 Juelich, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't