69853-42-5Relevant academic research and scientific papers
A method for preparing high-content bilirubin IX[alpha] from bilirubin IX[alpha] diester
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Paragraph 0028; 0041-0043; 0050-0055, (2019/04/10)
A method for preparing high-content bilirubin IX[alpha] from bilirubin IX[alpha] diester is disclosed, belonging to the field of bilirubin IX[alpha] preparation. The method includes following steps (aroute including firstly hydrolysis and then reduction): a step of adding dropwise a methanol solution of sodium hydroxide into an alcohol solution of bilirubin IX[alpha] diester, adding water, then performing hydrolysis, adjusting pH to 4-5 with a weak acid, performing rotary evaporation to remove a solvent, washing a product with water to remove inorganic salt, and performing vacuum drying to obtain bilirubin IX[alpha]; and a step of adding a free radical scavenger (stabilizer) into an alcohol solution of the bilirubin IX[alpha], adding a reductant that is borohydride, adding an acetone immediately after reduction is finished to decompose the excessive reductant, then adjusting pH to 4-5 with weak acid, performing rotary evaporation to remove a solvent, performing water washing, and performing purification with methanol and chloroform to obtain bilirubin IX[alpha] the purity of which is more than 97%. The method has characteristics of no need of chromatographic separation, mild reaction conditions, low cost, and convenient operation, and is suitable for industrial large-scale production.
Induction of wavelength-dependent photochemistry in bilirubins by serum albumin
McDonagh, Antony F.,Agati, Giovanni,Lightner, David A.
, p. 649 - 660 (2007/10/03)
Quantum yields for Z ? E photoisomerization of the natural bi-chromophore bilirubin IXα in ammoniacal methanol solution were found to vary with excitation wavelength, whereas no variation (within experimental error) was observed for xanthobilirubic acid and for symmetrically substituted bilirubins (bilirubin IIIα, bilirubin XIIIα, and mesobilirubin XIIα) in the same solvent. The quantum yield for Z ? E photoisomerization of xanthobilirubic acid bound to human serum albumin was also invariant with excitation wavelength. In contrast, quantum yields for Z ? E photoisomerization of the symmetrically-substituted bilirubins did show marked excitation wavelength dependency when they were bound to human serum albumin. These results show that quantum yields for Z ? E photoisomerization of bilirubins are markedly sensitive to protein binding and to the nature of pyrrole ring β-substituents. They also demonstrate that wavelength-dependent photochemistry is characteristic of bilirubins with non-identical pyrromethenone chromophores, as expected from exciton coupling theory, and that complexation with albumin induces wavelength-dependent photochemistry in symmetrically substituted bilirubins.
Effect of the Binding Sites of Human Serum Albumin on the Efficiency and Photostationary State Isomer Ratios of the Photoisomerization of Bilirubin
Kanna, Yoko,Arai, Tatsuo,Tokumaru, Katsumi
, p. 2758 - 2762 (2007/10/02)
The quantum yields of the isomerization and photostationary state isomer ratios of the photoisomerization of (4Z,15Z)-bilirubin IXα (ZZ-BR) were determined in an aqueous buffered solution in the presence of human serum albumin (HSA) at a molar ratio of / from 0.5 to 2.The BR isomer compositions in the photostationary state were constant at /=0.5-0.7.With increasing / from 0.8 to 2, the ZZ-BR composition in the photostationary state increased from 58 to 75percent, but the ZE-BR composition decreased from 39 to 22percent.The quantum yields in the isomerization of ZZ-BR to ZE-BR (ΦZZ->ZE) and a cyclized product, lumirubin (LR), (ΦZZ->LR), remained unvaried up to /=1, but ΦZZ->ZE decreased while ΦZZ->LR increased along with a further increase of /.These results are explained by the existence of two binding sites, a first-class site and a second-class site, for bilirubin binding to HSA; ΦZZ->ZE in the second-class site (=0.035) was as low as 1/3 of that in the first-class site (=0.11), but ΦZZ->LR in the second-class site (=4.2*10-3) was nearly two-times higher than that in the first-class site (=2.4*10-3).
Photoisomerization of Bilirubins and the Role of Intramolecular Hydrogen Bonds
Kanna, Yoko,Arai, Tatsuo,Tokumaru, Katsumi
, p. 1482 - 1489 (2007/10/02)
The quantum yields and the photostationary state isomer in the photoisomerization of bilirubin are strongly governed by the properties of the reaction media.Among the reaction media examined, the quantum yields for ZZ->ZE isomerization (φZZ-ZE) and for cyclization (φLR) were the highest in buffered aqueous solution (potassium phosphate buffer, pH 7.4) containing human serum albumin (HSA) in a 1:1 molar ratio to ZZ-BR, 0.11 and 2*10-3, respectively, on 436 nm irradiation.The effects of the reaction media surrounding bilirubin are discussed.
Effect of Serum Albumins from Several Mammals on the Photoisomerization of Bilirubin
Kanna, Yoko,Arai, Tatsuo,Tokumaru, Katsumi
, p. 1586 - 1588 (2007/10/02)
ZZ-Bilirubin undergoes photoisomerization to configurational (ZE and EZ isomers) and structural (LR) isomers in buffered aqueous solution containing serum albumins.The efficiency and the course of the isomerization are very much dependent on the mammals from which serum albumins are taken.
Effects of Solvents and Media on the Efficiency and Course of Photoisomerization of Bilirubins
Kanna, Yoko,Arai, Tatsuo,Sakuragi, Hirochika,Tokumaru, Katsumi
, p. 631 - 634 (2007/10/02)
The quantum yields of photoisomerization of bilirubin to various isomers were determined in various solvents.A specific photoisomerization took place only in buffered solutions containing human serum albumin.We discuss the effects of solvents and media surrounding bilirubin on its photoisomerization.
The Structure of "Photobilirubin"
Falk, Heinz,Mueller, Norbert,Ratzenhofer, Michael,Winsauer, Karl
, p. 1421 - 1432 (2007/10/02)
Anaerobic irradiation of bilirubin in the region of the main absorption band produces the diastereomers of (Z,E)- and (E,Z)-configurations with high quantum yield.The structure of these "photobilirubins" is proven by a chemical correlation with the corresponding diastereomers of biliverdindimethylester characterised before.Their 1H-NMR spectroscopic features have been recorded and are discussed. - Keywords: (Z,Z)-, (Z,E)- and (E,Z)-Bilirubin; Photobilirubin; Neonatal jaundice; Phototherapy
