抄録
The circular dichroism (CD) and absorption spectra of the ternary system, lutein-ovalbuminlipid, were studied in relation to the previously reported novel optical activity acquired when lutein formed a complex with some proteins [Agric. Biol. Chem., 44, 2111 (1980); 45, 1159 (1981)]. The CD spectrum of the system varied markedly with the amount of lipid added. On molar basis, the effect of the lipids tested decreased in the order of oleate and elaidate-linoleate-lecithin, while laurate has no effect. The observed phenomena may be interpreted in six ways, (a) the primary action of the added lipid is to remove lutein from the lutein-ovalbumin complex, (b) the complex between lutein and the lipid thus formed shows a CD qualitatively similar to but quantitatively different from that of the lutein-ovalbumin complex, (c) such CD can be observed with a lutein-lipid complex in which the latter is achiral, and thus can be ascribed to the presence of oligomeric aggregates of lutein with a chiral nature in mutual orientation, (d) the lipids act only as solubilizing agents of the aggregates, (e) the presence of two or more kinds of different optically active species in the ternary system produces the apparently complicated CD spectra, (f) the optical activity disappears completely and once the absorption spectrum of lutein is blue-shifted, it returns to the normal pattern when all lutein molecules are solubilized monomerically into micelles of lipid now abundant from the excess addition.
