ZfN: Search Results

1	Author	Peter Westhoff, Kurt Zimmermann, Frank Boege, Klaus Zetsche	Requires cookie*
	Title	Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits
	Abstract	Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -1 5 fold increase in the amount o f the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions o f large and small subunits o f the enzyme do not change. Their ratio is close to 3.4, the proportions in weight o f the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors o f protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis o f the large and small subunits of ribulosebisphosphate carboxylase.
	Reference	Z. Naturforsch. 36c, 942 (1981); received July 18 1981
	Published	1981
	Keywords	Ribulose-1, 5-bisphosphate Carboxylase, Synthesis, Subunits, Regulation, Phytoflagellate Chlorogonium elongatum
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	TEI-XML for	default:Reihe_C/36/ZNC-1981-36c-0942.pdf
	Identifier	ZNC-1981-36c-0942
	Volume	36

2	Author	GünterF. Wildner, PrafullachandraV. Sane, Jürgen Henkel	Requires cookie*
	Title	The Activation of Ribulose-l,5-bisphosphate Carboxylase-Oxygenase from Spinach by Oxygen Changes of the Enzyme Conformation during Air-Argon Transitions
	Abstract	The effect of oxygen on ribulose-l,5-bisphosphate carboxylase-oxygenase from spinach was in vestigated. Both activities were deactivated by removal of oxygen and reversibly reactivated by oxygenation of the enzyme solution. The change in enzyme activities was accompanied by confor mational changes as studied by the use of intrinsic and extrinsic fluorescent probes. The analysis of cysteine sulfhydryl groups accessible to 5,5'-dithiobis-(2-nitrobenzoic acid) re vealed that the number of these groups changed with the oxygen concentration. The kinetic of the exposure of eight cysteine residues was similar to the loss of enzyme activities. The modification of these groups with 5,5'-dithiobis-(2-nitrobenzoic acid) caused almost complete loss of both the activities. The enzyme isolated from a photolithotrophic organism, Chromatium vinosum, was not affected by oxygen removal. During air — argon transitions, neither the enzyme conformation nor the num ber of accessible sulfhydryl groups changed.
	Reference	Z. Naturforsch. 35c, 239—248 (1980); received December 12 1979
	Published	1980
	Keywords	Ribulose-l, 5-bisphosphate Carboxylase, Ribulose-l, 5-bisphosphate Oxygenase, Enzyme Confor mation, Oxygen Effect, Photosynthesis
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	TEI-XML for	default:Reihe_C/35/ZNC-1980-35c-0239.pdf
	Identifier	ZNC-1980-35c-0239
	Volume	35