[NMR studies of glycerol permeability in lipid vesicles, erythrocytes and the alga Dunaliella].
Glycerol diffusional permeabilities through the cytoplasmic cell membrane of Dunaliella salina, the cell envelope of pig erythrocyte and egg phosphattidylcholine vesicles were measured by NMR spectroscopy employing the spin-echo method and nuclear T1 relaxation. The following permeability coefficients (P) and corresponding enthalpies of activation (delta H not equal to ) were determined for glycerol at 25 degree C: for phosphatidylcholine vesicles 5 . 10-6 cm/s and 11 +/- 2 kcal/mol; for pig erythrocytes 7 . 10-8 cm/s and 18 +/- 3 kcal/mol, respectively; for the cytoplasmic membrane of D. salina the permeability at 17 degrees C was found to be exceptionally low and only a lower limit (P less than 5 . 10-11 cm/s) could be calculated. At temperatures above 50 degree C a change in membrane permeability occurred leading to rapid leakage of glycerol accompanied by cell death. The data reinforce the notion that the cytoplasmic membrane of Dunaliella represents a genuine anomaly in its exceptional low permeability to glycerol.
D000818:Animals; D002151:Calorimetry; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D000460:Chlorophyta / Q000378:metabolism*; D004058:Diffusion; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D006358:Hot Temperature; D008081:Liposomes; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D008954:Models, Biological; D010713:Phosphatidylcholines; D013552:Swine
D008081:Liposomes; D010713:Phosphatidylcholines; D005990:Glycerol