Linked Life Data

6833234

Source:http://linkedlifedata.com/resource/pubmed/id/6833234

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1983-5-5
pubmed:abstractText
The phase behavior of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE) in excess water has been studied by differential scanning calorimetry and x-ray diffraction. In addition to the usual gel phase L beta of lamellar periodicity 5.07 nm and the fluid bilayer phase L alpha of periodicity 4.5 nm, two distinct crystalline forms may also be spontaneously adopted. The L beta phase is only produced by cooling from L alpha and is metastable, relaxing to one of the crystalline forms on incubation. One crystalline polymorph, designated beta 2, has a lamellar periodicity of 4.55 nm and corresponds to the structure of DLPE crystallized from a variety of organic solvents. The other crystalline polymorph, designated beta 1, has a lamellar periodicity of 3.78 nm, which implies that in this form the hydrocarbon chains are tilted at approximately 40 degrees to the bilayer normal. The beta 2 polymorph is obtained on dispersing crystalline DLPE directly in water at T less than 43 degrees C, on incubation in the L alpha phase at 30 degrees C less than T less than 43 degrees C, or on heating the beta 1 form slowly to T greater than 35 degrees C. The beta 1 polymorph is obtained on incubating the L beta phase at T less than 30 degrees C. By calorimetry, the L beta phase undergoes an endothermic transition (delta H = 15.5 kJ X mol-1 (3.7 kcal X mol-1)) at 30.6 degrees C to the fluid bilayer phase L alpha. The beta 1 phase undergoes an endothermic transition (delta H congruent to 50 kJ X mol-1 (12 kcal X mol-1)) to L alpha at 35 degrees C. The beta 2 phase undergoes an endothermic transition (delta H = 57 kJ X mol-1 (13.7 kcal X mol-1)) to L alpha at 43 degrees C.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3850-4
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Metastability and polymorphism in the gel and fluid bilayer phases of dilauroylphosphatidylethanolamine. Two crystalline forms in excess water.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't