Properties of a fluorescent analog of the pyrethroids

The ester of pyrene-1-methanol with cis-2,2-dimethyl-3(2,2-dichlorovinyl) cyclopropane carboxylic acid (cis-permethrin acid) is introduced as a fluorescent analog of the pyrethroids. Relative intensities of the vibronic bands in the fluorescence emission spectrum of the ester in lipid bilayers are consistent with a location for the pyrene group in the glycerol backbone region of the bilayer. It is suggested that pyrethroids adopt a “horseshoe” conformation in the bilayer with the ester group at the lipid-water interface. Fluorescence data are interpreted in terms of one binding site per four lipids. In the (Ca²⁺Mg²⁺)-ATPase system prepared from muscle sarcoplasmic reticulum, the ester binds both to sites in the lipid and on the ATPase. There are a large number of sites for the ester on the ATPase. For the ATPase reconstituted with the short chain lipid dimyristoleoylphosphatidylcholine, the ester causes an increase in activity comparable to that caused by the pyrethroids.