ZfN: Search Results

1	Author	Friederike Koenig, Wilhelm Menke, Hans Craubner, GeorgH. Schmid, Alfons Radunz	Requires cookie*
	Title	Photochemically Active Chlorophyll-Containing Proteins from Chloroplasts and their Localization in the Thylakoid Membrane
	Abstract	After solubilization of stroma-freed chloroplasts with deoxycholate, the lipids and the detergent used are separated from the proteins by gel filtration. In this way not denatured pigment-con-taining protein preparations were obtained. The particles in fraction 1 exhibited a molecular weight of 600 000 and contained an average of 25 chlorophyll molecules. The circular dichroism spectrum showed exciton splitting of the red band. The particles in fraction 2 contained 1 chloro-phyll molecule and exhibited a molecular weight of 110 000. The particles in fraction 3 also contained only 1 chlorophyll molecule and had a molecular weight of between 80 000 and 100 000. Pure preparations of fraction 1 only carried out the methylviologen M e h 1 e r reaction with the dichlorophenol indophenol/ascorbate couple as electron donor. Fraction 3 only reduced ferri-cyanide with diphenylcarbazide as an electron donor in the light. Fraction 2 exhibited both the photosystem I reaction and the photosystem II reaction. An antiserum to extracted fraction 1 does not inhibit electron transport in the intact lamellar system. The photoreduction of methylviologen is only inhibited after disruption of the thylakoids. The antiserum to fraction 2 inhibits the photo-reduction of methylviologen in the intact lamellar system. Consequently, one inhibition site for this photosystem I reaction must be located on the inner and another on the outer surface of the thylakoid membrane. In addition, antibodies to fraction 1 are specifically adsorbed onto the lamellar system without any effect on electron transport and without a concomitant agglutination. Antibodies to fraction 3 partially inhibit the photoreduction of ferricyanide with diphenylcarbazide as an electron donor in the intact lamellar system. Hence, the inhibition site of this system II reaction is located on the outer surface of the thylakoids. We have reason to believe that the inhibition sites not reacting are located in the partitions, which are not accessible to antibodies.
	Reference	(Z. Naturforsch. 27b, 1225 [1972]; received July 5 1972)
	Published	1972
	Keywords	Chloroplasts, membranes, proteins, photosynthesis, antibodies
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	TEI-XML for	default:Reihe_B/27/ZNB-1972-27b-1225.pdf
	Identifier	ZNB-1972-27b-1225
	Volume	27

2	Author	G. Segewitz	Requires cookie*
	Title	Liganden-und Isotopenaustausch im System: Serumproteine — Zink — Polyaminopolycarbonsäuren Ligand and Isotope Exchange in the System: Serum Proteins — Zinc — Polyaminopolycarbonic Acids
	Abstract	In vitro-studies show that the Ca-chelates of EDTA and DTPA are equally effective in removing Zn from the proteins and that the Zn-protein pool is composed of several fractions with different stabilities. Only a small fraction of the protein-bound Zn can be labelled by 65 Zn in vitro and, as to the mobilization of 65 Zn, Ca-DTPA was found to be 20 times more effective than equimolar Ca-EDTA. The isotope exchange between Zn-DTPA and protein-bound 65 Zn is an extremely fast reaction whereas in the case of Zn-EDTA a sluggish exchange takes place. The analysis of the results led to conclusion that the ligand and isotope exchange reactions in the case of EDTA proceed via the free Zn 2+ -ion; with the high-dentate DTPA, however, the formation of ternary and mixed complexes plays an important role. The implications of the findings as related to the toxi-city of the Ca-chelates are discussed.
	Reference	(Z. Naturforsch. 27b, 1370—1375 [1972]; eingegangen am 14. Juli 1972)
	Published	1972
	Keywords	Zinc, Radiozinc, Proteins, Ethylenediaminetetraacetate, Diethylenetriaminepentaacetate
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	TEI-XML for	default:Reihe_B/27/ZNB-1972-27b-1370.pdf
	Identifier	ZNB-1972-27b-1370
	Volume	27