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1986 (1)
1982 (1)
1Author    W. Küfer, H. ScheerRequires cookie*
 Title    Rubins and Rubinoid Addition Products from Phycocyanin  
 Abstract    The verdin-type Chromophore o f denatured C-phycocyanin (1) from Spirulina platensis is reduced to the corresponding rubin (2 a) by sodium borohydride. The structure assigned is in agreement with the uv-vis spectroscopic properties of the product and was deduced from model studies with free bile pigments. Analogous model studies using sodium dithionite demonstrated a two-fold reactivity for this reagent, leading to products which are both o f the rubin spectral type under the conditions tested. True rubins (10,22-dihydrobilindions) are formed in low yield only if an excess o f reagent is used in methanol/water mixtures. It is accompanied by polar addition product(s) o f the same spectral type, which are generally formed exclusively. In particular, no bilirubin was formed under the reaction conditions previously applied for the chemical modification o f phycobiliproteins and phytochrome. From this finding and from the strikingly different properties o f the borohydride and dithionite products, o f phycocyanin upon renaturation, the dithionite product is suggested to be a rubinoid addition product (2 b) rather than a hydrogenation product. In contrast to the dithionite addition product 2 b of phycocyanin, the chromophore o f the true phycorubin (2 a) remains stable upon renaturation. The uv-vis spectral properties of the chromophore are not markedly different whether the apoprotein is in its native or denatured state. The different electrophoretic mobilities o f native (renatured) phycocyanin compared to the renatured borohydride product suggest that these two have different protein conformations. The preparation of these phycorubins renders the extensive techniques o f bilirubin chemistry applicable in the study o f biliproteins. 
  Reference    Z. Naturforsch. 37c, 179—192 (1982); received December 151981 
  Published    1982 
  Keywords    Phycocyanin, Phycorubin, Bile Pigments, Biliverdin, Bilirubin 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0179.pdf 
 Identifier    ZNC-1982-37c-0179 
 Volume    37 
2Author    W. Kufer, O. Schmid, G. Schmidt, H. ScheerRequires cookie*
 Title    The Diazo Reaction of Bilirubins and Phycorubins: A Quantitative Study  
 Abstract    A quantitative study o f the diazo reaction has been made with several bilirubins including a 2,3-dihydrobilirubin and several phycorubins. The latter have been prepared from the integral phy-cocyanin o f two cyanobacteria (M astigocladus laminosus and Spirulina platen sis), and from the phycocyanin subunits. T hese phycorubins have been subjected to the diazo reaction in order to test for the presence o f a second covalent chromophore protein bond in the latter. 
  Reference    Z. Naturforsch. 41c, 437—452 (1986); received Novem ber 21 1985 
  Published    1986 
  Keywords    Photosynthesis, Phycobiliproteins, A ntenna, Bile Pigm ents, Biliverdin 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0437.pdf 
 Identifier    ZNC-1986-41c-0437 
 Volume    41