Linked Life Data

10209211

Source:http://linkedlifedata.com/resource/pubmed/id/10209211

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1999-6-1
pubmed:abstractText
The transmembrane diffusion and equilibrium distribution of spin-labelled phosphatidylethanolamine (PE*), phosphatidylcholine (PC*) and cardiolipin (CL*) were investigated in purified mitochondrial inner membranes using electron spin resonance spectroscopy. Using the back exchange technique, we found that the outside-inside movement of PE* and PC* in beef-heart inner mitochondrial membranes was rapid (t1/2 in the range 10-15 min at 30 degrees C). The steady-state distributions in non-energised mitoplasts were approximately 30% in the inner leaflet for PC* and 39% for PE*. Within the limits of probe concentration that can possibly be used in these experiments, the initial velocity of the inward movement was not saturable with respect to the amount of analogue added to the membranes, suggesting that the spin-labelled phospholipids diffused passively between the two leaflets of the inner mitochondrial membrane. In energised mitoplasts, PC* behaviour was not affected, PE* diffused approximately two times faster toward the inner monolayer but reached the same plateau. Treatment of energised mitochondria with N-ethylmaleimide did not affect PC* diffusion, while the kinetics of PE* internalisation became identical to that of PC*. Similar results were found when PC* and PE* movements were studied in mitoplasts from beef heart, rat liver or yeast. The spin-labelled cardiolipin, which possesses four long chains, had to be introduced in the mitoplast with some ethanol. After equilibration (t1/2 of the order of 13 min at 30 degrees C), the transmembrane distribution suggested that approximately half of the cardiolipin analogue remained in the outer leaflet. These results do not allow us to determine if a specific protein (or flippase) is involved in the phospholipid transmembrane traffic within inner mitochondrial membranes, but they show that lipids can rapidly flip through the mitochondrial membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
1418
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
61-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Transbilayer movement and distribution of spin-labelled phospholipids in the inner mitochondrial membrane.
pubmed:affiliation
Institut de Biotechnologie, Faculté des Sciences, 123 avenue A. Thomas, 87060, Limoges cedex, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't