Control of delta-aminolaevulate synthetase activity in Rhodopseudomonas spheroides.
1. delta-Aminolaevulate synthetase from Rhodopseudomonas spheroides grown semi-anaerobically undergoes a spontaneous activation during the first hour after the disruption of cells when homogenates are stored at 4 degrees . 2. After cultures of R. spheroides growing semi-anaerobically are oxygenated no activation of delta-aminolaevulate synthetase occurs in cell extracts. Cessation of activation in extracts is almost complete 10min. after oxygenation of cells has begun. 3. A heat-stable fraction of low molecular weight from semi-anaerobic cells reactivates delta-aminolaevulate synthetase in extracts of oxygenated cells and appears to contain a compound responsible for the spontaneous activation. 4. A heat-stable fraction of low molecular weight from oxygenated cells inhibits the spontaneous activation in extracts of semi-anaerobic cells. 5. The effect of oxygen on the rate of bacteriochlorophyll synthesis in R. spheroides may be mediated through alterations in the concentrations of a low-molecular-weight activator and inhibitor of delta-aminolaevulate synthetase.
D000596:Amino Acids / Q000378:metabolism; D002734:Chlorophyll / Q000096:biosynthesis; D000860:Hypoxia / Q000378:metabolism; D007982:Levulinic Acids / Q000378:metabolism; D008025:Ligases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism; D012241:Rhodopseudomonas / Q000201:enzymology*; D014020:Tissue Extracts / Q000494:pharmacology
D000596:Amino Acids; D007982:Levulinic Acids; D014020:Tissue Extracts; D002734:Chlorophyll; D008025:Ligases; D010100:Oxygen