These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Study of water permeability through phospholipid vesicle membranes by 17O NMR.
    Author: Haran N, Shoporer M.
    Journal: Biochim Biophys Acta; 1976 Apr 05; 426(4):638-46. PubMed ID: 1259988.
    Abstract:
    Vesicle suspensions of up to 5% egg lecithin and 2.5% cholesterol have been found to have no effect on the NMR relaxation times of 17O from water. Addition of 1-5 mM Mn2+ to an equimolar vesicle suspension of egg lecithin and cholesterol permitted resolution of the free induction decay into two exponential components, a fast one arising from the external water and a slow one arising from the intravesicular fluid. From the rates of relaxation the mean life time of the water molecules within the vesicles was calculated to be 1+/- 0.1 ms at 22 degrees C. The size of the vesicle was estimated from electron micrographs to be about 500 A in diameter. These data yield an equilibrium water permeability, Pw, of about 8 mus-1 for the vesicle membranes. From the temperature dependence of Pw an activation energy of 12+/-2 kcal/mol was obtained. The longitudinal relaxation time (T1) of water within vesicles remained the same as in pure water.
    [Abstract] [Full Text] [Related] [New Search]