ZfN: Search Results

1	Author	Hugo Scheer, W. Erner Kufer	Requires cookie*
	Title	Conformational Studies on C-Phycocyanin from Spirulina platensis
	Abstract	The chromophore-protein interactions of C-phycocyanin (C-PC) from Spirulina platensis have been studied by following the partial and complete denaturation with UV-Vis spectroscopy. From comparison with published MO calculations, an elongated conformation of the chromophore is sug gested for native C-PC, a cyclic one for denatured C-PC. By means of partial denaturation, a step wise unfolding of the protein has been demonstrated. The presence of at least two sets of spectro scopically different diromophores is suggested from the partial denaturation and low temperature experiments.
	Reference	(Z. Naturforsch. 32c, 513 [1977]; received April 25 1977)
	Published	1977
	Keywords	Bile Pigments, Protein Interaction, Conformation, Denaturation
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	TEI-XML for	default:Reihe_C/32/ZNC-1977-32c-0513.pdf
	Identifier	ZNC-1977-32c-0513
	Volume	32

2	Author	W. Olfhart Rüdiger, Thom As Brandlmeier, Inge Bios, Jens-Peter Gossauer, Weller	Requires cookie*
	Title	Isolation of the Phytochrome Chromophore. The Cleavage Reaction with Hydrogen Bromide A lbert
	Abstract	The cleavage o f the bilin chromophore from C-phycocyanin with hydrogen bromide yields 3E-configurated phycocyanobilin (4) as the major and 3 Z-configurated phycocyanobilin (5) as the minor reaction product. The reaction o f synthetic 3E-configurated phytochromobilin (2) with hydrogen bromide and methanol leads only to a methanol adduct at the C-18 side chain (7) whereas the same reaction with the 3Z-configurated phytochromobilin (3) leads to 7 and 2. The bilin chromophore was cleaved also from phytochrome after preparation o f phytochromobilin peptides. The detection o f 2 and 7 suggested that 3Z-and 3E-configurated phytochromobilin were the primary products o f cleavage from phytochrome. A reaction scheme is given which can explain the results o f the reaction with hydrogen bromide and methanol.
	Reference	Z. Naturforsch. 35c, 763—769 (1980); received July 11 1980
	Published	1980
	Keywords	Phytochrome, Bile Pigments, Phytochromobilin, Thioether Cleavage, C-Phycocyanin
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	TEI-XML for	default:Reihe_C/35/ZNC-1980-35c-0763.pdf
	Identifier	ZNC-1980-35c-0763
	Volume	35

3	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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	TEI-XML for	default:Reihe_C/37/ZNC-1982-37c-0179.pdf
	Identifier	ZNC-1982-37c-0179
	Volume	37