Linked Life Data

114523

Source:http://linkedlifedata.com/resource/pubmed/id/114523

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
1979-12-18
pubmed:abstractText
Prephenate dehydratase from Bacillus subtilis was found to exist in three states of aggregation. A high molecular weight (210,000) species was fully active and the catalytic activity was unaffected by the effectors methionine or phenylalanine. Low concentrations of phenylalanine caused dissociation to a Mr = 55,000 dimer. Heating to 32 degrees C also caused dissociation, but cooling and adding substrate or methionine favored association. When no effectors were present the enzyme eluted from Sephadex columns as a monomer. Both methionine and phenylalanine shifted the equilibrium from the inactive monomer to the active dimeric enzyme. In the presence of a saturating methionine concentration, the dimer possessed the same high activity as did the 210,000-dalton form. Phenylalanine inhibited the dimer, but not the higher molecular weight form. A model involving only three types of sites (catalytic, association-activation, and inhibition) is consistent with the data. It is proposed that phenylalanine is the preferred metabolite for binding both effector sites on the dimer; it binds the association-activation site with higher affinity than the inhibition site, but binding at the latter site has a greater effect on the catalytic rate. Methionine, like phenylalanine, has a hydrophobic side chain but is accommodated only at the association-activation site.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
254
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10321-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Regulation and state of aggregation of Bacillus subtilis prephenate dehydratase in the presence of allosteric effectors.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.