[8] Carotenoid-protein complexes

The role of the carotenoids, lutein and zeaxanthin, in protecting against age-related macular degeneration: A review based on controversial evidence

“…In the mammalian eye, it has been reported that retinal tubulin binds macular carotenoids [59], possibly as a site for passive deposition in the tissue. Further postulations included the assumption that human macular membranes could be a rich source of specific binding proteins for the macular carotenoids, especially since many plant and invertebrate carotenoid-binding proteins are known to be membrane associated [60,61]. In a recent report, xanthophyll-binding proteins (XBP) were partially purified and isolated from the human macula and retina and it was shown that lutein and zeaxanthin bind specifically to these proteins [62].…”

Ligand-binding Characterization of Xanthophyll Carotenoids to Solubilized Membrane Proteins Derived from Human Retina

“…Although it has been hypothesized that at least a portion of the macular carotenoids may be freely dissolved in lipid bilayers (Bone et al, 1992;Sujak et al, 1999), simple membrane lipid solubilization of the macular carotenoids would be unlikely to be able to account for the high degree of speci®city of lutein and zeaxanthin uptake into the primate retina. It is not unreasonable to assume that human macular membranes could be a rich source of speci®c binding proteins for the macular carotenoids, especially since many plant and invertebrate carotenoid-binding proteins are known to be membrane-associated (Lakshman and Okoh, 1993;Reddy et al, 1993).…”

“…The plant and algal proteins are usually involved in photosynthesis or photoprotection. Prominent examples include several membrane-associated and water-soluble carotenoid-binding proteins isolated from cyanobacteria, prochlorophytes and higher plants that bind various xanthophylls and/or carotenes (Lakshman and Okoh, 1993;Reddy, Bullerjahn and Sherman, 1993). a-Crustacyanin is the 350 kDa astaxanthin-binding protein responsible for the color of lobster shells (Zagalsky, 1995).…”

Behavior of Pigment Cells Closely Correlates the Manner of Gastrulation in Sea Urchin Embryos

“…As is well known, pigment cells in sea urchin embryos contain carotenoids and naphthoquinones (Monroy et al, 1951;Griffiths, 1966;Matsuno and Tsushima, 2001). Fixation with formalin is thought to destruct carotenoids-protein complex (Lakshman and Okoh, 1993), resulting in the emission of autofluorescence under UV-or G-illumination. Although it has been known that some genes, such as SpHmx (Martinez and Davidson, 1997), S9 and CyIIa (Miller et al, 1996), are expressed specifically in pigment cells, timing of the specific expression of these genes does not differ from the timing of pigment granule accumulation.…”