Lutein-cholorophyll-alpha energy transfer in detergent micelles.

Abstract

Absorption, fluorescence and fluorescence excitation spectra were determined for equimolar mixed micellar detergent solutions of lutein and chlorophyll-a in the concentration range from 9·10−6 to 1.8·10−4 M, with detergent (triton-X100) concentrations from 3·-10−4 to 7·10−3 M. In the range of detergent concentrations studied the pigments incorporated into the detergent micelles attained a high local concentration (0.1 to 0.01 M), reminiscent of pigment concentration within the chloroplast. A lutein → chlorophyll-a energy transfer with an efficiency of about 15% was found in these systems. In dilute (9·10−6 M) pigment solution with concentrated (7·10−3 M) detergent practically no transfer is observed. The extent of aggregation and the efficiency of transfer depend on the composition of the system. The aggregation of chlorophyll-a is partly inhibited by lutein molecules. It is shown that the energy transfer efficiency as function of distance follows anr−3 relationship,R0 being 22 a.