Absorption spectra xanthophylls

All lutl alleles are recessive mutations (Fig. 3 A) that accumulate an additional carotenoid with an HPLC retention time and UV/visible absorption spectrum characteristic of a monohydroxy / , e-carotenoid (an a-carotene derived xanthophyll). The identification of the accumulating compound as zeinoxanthin ()3,e-caroten-3-ol) was confirmed by mass spectrometry (Pogson et al., 1996). The only difference between lutein and zeinoxanthin is the presence of an hydroxyl group on carbon 3 of the -ring in lutein. The decrease in lutein and its partial replacement by its immediate precursor, zeinoxanthin, defines lutl as a mutation... 

The gradual addition of water to an acetone solution of lutein causes marked changes in the structure of the absorption spectrum (Fig.4). In the first step only a short-wavelength absorbing form with one maximum is formed. The LWAF appears in the second step. It may then be concluded that the crystalline lutein and presumably some other xanthophylls are accompanied by non-crystalline forms of the pigments. 

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