Fatty acid transport across lipid bilayer planar membranes.
The transport of palmitic acid (PA) across planar lipid bilayer membranes was measured using a high specific activity [14C]palmitate as tracer for PA. An all-glass trans chamber was employed in order to minimize adsorbance of PA onto the surface. Electrically neutral (diphytanoyl phosphatidylcholine) and charged (Azolectin) planar bilayers were maintained at open electric circuit. We found a permeability to PA of (8.8 +/- 1.9) x 10(-6) cm s(-1) (n = 15) in neutral and of (10.3 +/- 2.2) x 10(-6) cm s(-1) (n = 5) in charged bilayers. These values fall within the order of magnitude of those calculated from desorption constants of PA in different vesicular systems. Differences between data obtained from planar and vesicular systems are discussed in terms of the role of solvent, radius of curvature, and pH changes.
Romano-Fontes
L G
LG
Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biomédicas, Universidade de São Paulo, Brazil.
Curi
R
R
Peres
C M
CM
Nishiyama-Naruke
A
A
Brunaldi
K
K
Abdulkader
F
F
Procopio
J
J
D001692:Biological Transport; D002250:Carbon Radioisotopes; D005227:Fatty Acids / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism*; D019308:Palmitic Acid / Q000378:metabolism; D010539:Permeability
D002250:Carbon Radioisotopes; D005227:Fatty Acids; D008051:Lipid Bilayers; D019308:Palmitic Acid