title: Properties of astaxanthin/Ca2+ complex formation in the deceleration of cis/trans isomerization.
abstract: Deceleration of the regioselective cis/trans isomerization of all-trans-astaxanthin (ASTX) in the presence of Ca2+ was shown by HPLC analysis. The NMR and ITC analyses provided evidence for complexation of ASTX with Ca2+ in 1:2 stoichiometry via chelation at both carbonyl and hydroxyl groups. The rotation across torsion omega6 (C5-C6-C7-C8) upon complexation is consistent with the NOE between 7-H and 5-CH3. This study supports the inhibitory effect of ASTX on calcium-induced turbidity of lens crystallins.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Chien-Sheng
authors.initials: CS
authors.lastname: Chen
authors.forename: Shih-Hsiung
authors.initials: SH
authors.lastname: Wu
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Wu
authors.forename: Jim-Min
authors.initials: JM
authors.lastname: Fang
authors.forename: Tzu-Hua
authors.initials: TH
authors.lastname: Wu
mesh_terms: D002118:Calcium / Q000737:chemistry* / Q000494:pharmacology; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D003459:Crystallins / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics; D024341:Xanthophylls / Q000097:blood / Q000737:chemistry / Q000494:pharmacology
chemical_list: D003459:Crystallins; D024341:Xanthophylls; C005948:astaxanthine; D002118:Calcium