Aggregation, Configuration and Particle Size of Lutein Dispersed by Sodium Dodecyl Sulfate in Various Salt Concentrations

The CD spectrum of lutein drastically changed with added amounts of sodium dodecyl sulfate (SDS) in buffers (pH 7.0) at phosphate concentrations below 70 mm. The CD pattern was inverted at particular binding ratios of SDS to the lutein, depending on the lutein concentration. The ratios were 30, 15 and 10 for lutein concentrations below 3 µm, between 3 and 8 µm, and above 8 µm, respectively. The sedimentation analysis showed strong dependence of the aggregate size of lutein on both the SDS and phosphate concentrations. The size became larger with a decrease of SDS concentration and with an increase of the salt. The sedimentation constants of these aggregates were small in comparison with those expected on the basis of parallel filtration measurements, suggesting that the aggregate was considerably porous. These results indicate that the size of the lutein aggregate is larger than 4500 A as far as the ordinary CD pattern remains and it becomes smaller as the ordinary pattern changes to the inverted one. A c...