Fluorescent cholesteryl esters in the core of low density lipoprotein

Fluorescent cholesteryl esters with chromophores placed either on the acyl chain (cholesteryl-$\text{cis}$-parinarate), the sterol ring system (5,7,9-cholesteryl oleate), or the side chain (naphthylcholenamide oleate) have been incorporated into the core of low density lipoprotein. The temperature dependence of several fluorescence parameters has been evaluated. An analysis of the fluorescence lifetime components of cholesteryl-$\text{cis}$-parinarate reveals coexisting environments whose proportion varies and reflects the thermotropic reorganization of the core of the particle. An analysis of the motion by dynamic depolarization suggests that the motions of the acyl chains in the core of the particle are highly restricted.