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Ligand-binding characterization of xanthophyll carotenoids to solubilized membrane proteins derived from human retina


, : Ligand-binding characterization of xanthophyll carotenoids to solubilized membrane proteins derived from human retina. Experimental Eye Research 72(4): 381-392

The macula of the human retina contains extraordinarily high concentrations of lutein and zeaxanthin, xanthophyll carotenoids that appear to play an important role in protecting against age-related macular degeneration, the leading cause of blindness among the elderly. It is likely that the uptake and stabilization of these carotenoids is mediated by specific xanthophyll-binding proteins. In order to purify and characterize such a binding protein, a carotenoid-rich membrane fraction derived from human macula or peripheral retina was prepared by homogenization, differential centrifugation, and detergent solubilization. Further purification was carried out using ion-exchange chromatography and gel-filtration chromatography coupled with continuous photodiode-array monitoring for endogenously associated xanthophyll carotenoids. The most highly purified preparations contained two major protein bands at 25 and 55 kDa that consistently co-eluted with endogenous lutein and zeaxanthin. The visible absorbance spectrum of the binding protein preparation closely matches the spectral absorbance of the human macular pigment, and it is bathochromically shifted about 10 nm from the spectrum of lutein and zeaxanthin dissolved in organic solvents. Binding of exogenously added lutein and zeaxanthin is saturable and specific with an apparent Kd of approximately 1 microM. Canthaxanthin and beta-carotene exhibit no significant binding activity to solubilized retinal membrane proteins when assayed under identical conditions. Other potential mammalian xanthophyll-binding proteins such as albumin, tubulin, lactoglobulin and serum lipoproteins possess only weak non-specific binding affinity for carotenoids when assayed under the same stringent binding conditions. This investigation provides the first direct evidence for the existence of specific xanthophyll-binding protein(s) in the vertebrate retina and macula. The possible roles of xanthophyll-binding proteins in normal macular function and in the pathogenesis of age-related macular degeneration remain to be elucidated.

US$19.90

PMID: 11273666

DOI: 10.1006/exer.2000.0965


Other references

Speake, D.L., 1988: Measuring metabolic-unit levels of activity in the well elderly. Journal of Community Health Nursing 5(3): 177-185

Coppola, R.; Striano, V., 1963: On Primary Sarcoma Of The Kidney. Rassegna Internazionale di Clinica E Terapia 43: 1115-1122

Trost, B.; Hipskind, P., 1992: A total asymmetric synthesis of the isolactarane sesquiterpene (-)-merulidial. A general strategy for the synthesis of lactaranes, marasmanes, sterpuranes as well as isolactaranes which share a common structural motif begins to emerge based upon a tandem Pd catalyzed cycloisomerization - thermal cycloaddition sequence.

Yamamoto, Y.; Ishihara, M.; Kirdani, R.Y.; Osawa, Y.; Sandberg, A.A., 1976: Studies of phenolic steroids in human subjects part 19 renal conjugation of 15 alpha hydroxy estradiol 3 sulfate. In order to elucidate further the role of the kidney in the conjugation and excretion of 15.alpha.-hydroxy-estrogens, 15.alpha.-hydroxyestradiol-3-sulfate (15.alpha.-OHE2-S) was synthesized doubly and singly labeled and its urinary excretory patte...

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