โ Scribed by Boll, M.
No coin nor oath required. For personal study only.
The effect of deoxycholate on a number of enzymatic activities with electron transport function from the particulate fraction of Rhodospirillum rubrum has been studied.
The activities are differently inactivated by DOC 1, the NADH oxidase system being the most sensitive-and ~qADH dehydrogenase the least sensitive enzymatic activity. NADH-and succinate-cytochrome e-reductase are Mso rapidly inactivated.
DOC/protein ratios smaller than those which lead to an inactivation stimulate NADH-and succinate-cy~oehrome c-rednctase. The activities are increased by over 1O0 percent. The stimulated activities are stable and are found to be still membrane bound.
NADH dehydrogenase with menadione as electron acceptor is stimulated by appr. 180 percent. The elevated activity is not stable. No increase in activity is found when DCPIP or ferrieyanide are used as electron acceptors.
~qADH dehydrogenase is partly (45 percent) solubilized by treatment with DOC. The activities can be separated by either fractionation with ammonium sulfate or by gelfiltration with Sephadex. The solubilized portion has a 4--5 fold higher specific activity than the untreated sample. The separated activities are both unstable, the solubilized portion being inactivated more rapidly.
Desoxyeholat auf eine Reihe yon enzymatischen Aktivit~ten mit Elektronentransportfunktion aus der Partikelfraktion yon 1L rubrum wurde untersueht. 1. Die Enzyme werden durch D0C unterschiedlich inaktiviert. Das NADH-Oxydasesystem ist die empfindliehste, NADH-dehydrogenase ist die stabilste Aktivit~t. NADH-und Succinat-Cytochrom c-Reduetase werden ebenfalls stark inaktiviert. 2. Ein niedrigeres Verh~ltnis DOC/Protein als das, welches zu einer Inaktivierung ffihrt, stimuliert die Aktivit~ten yon NADH-und Succinat-Cytochrom e-Reductase. Beide Aktivit~ten werden um mehr als 100~ gesteigert. Die erhShten Aktivit~ten sind stabil und sie sind darfiber hinaus noch vollst~ndig membrangebunden. 3. IqADH-Dehydrogenase mit Menadion als Electronenaeceptor wird um ca. 180~ stimuliert. Diese erhShte Aktivit~t ist nieht stabil. Mit DCPIP oder Ferricyanid als Elektronenaceeptor wird keine Stimulierung der Aktivit~t gefunden.
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NADH oxidation with the particulate fraction from dark aerobically grown Rhodospirillum rubrum is significantly stimulated by the addition of phosphate (Pi) and Mg ++, or Pi, Mg ++, ATP and the hexokinas~e-glucose system. Km values for Pi in NADH oxidation and phosphorylation are 10 -a ~ and 8 โข 10
The effects of transfer from low to high light intensity on membrane bound electrontransport reactions of Rhodospirillum rubrum were investigated. The experiments were performed with cultures which did not form bacteriochlorophyll (Bchl) for about two cell mass doublings during the initial phase of