| | 1 | Author
| W. Küfer, H. Scheer | Requires 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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| default:Reihe_C/37/ZNC-1982-37c-0179.pdf | | | | Identifier
| ZNC-1982-37c-0179 | | | | Volume
| 37 | |
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