Abstract
The interaction of 2, 4-dichlorophenoxyacetic acid (2, 4-D) with multi-lamellar vesicles of dimyristoyl and dipalmitoyl L-α-phosphatidylcholine was examined from the pH dependency of partition and pH-and temperature-dependent polarization of fluorescence probes such as 1, 6-Biphenyl-1, 3, 5-hexatriene. It was strongly suggested that 2, 4-D in the undissociated form was located at the region from the neighborhood of the glycerol backbone to a shallow site of the hydrophobic core of the lipid bilayers and that its anionic species was adsorbed at the membrane surface. Fluorescence study with the derivatives of 2, 4-D showed that hydrophobicity and pKa of these acids determined their interaction with membrane.
