%0 Journal Article %A Kaprálek, F. %A Pichinoty, F. %T The Effect of Oxygen on Tetrathionate Reductase Activity and Biosynthesis %D 1970 %J Microbiology, %V 62 %N 1 %P 95-105 %@ 1465-2080 %R https://doi.org/10.1099/00221287-62-1-95 %I Microbiology Society, %X SUMMARY: Cyanide (1 mm) strongly inhibited aerobic respiration, and 2,4 dinitrophenol (0·2 mm) apparently uncoupled oxidative phosphorylation, in nongrowing Citrobacter. At these inhibitor concentrations, anaerobic tetrathionate reductase activity was not much affected. Aeration inhibited tetrathionate reductase activity; 0·2 mm-2,4 DNP did not influence oxygen inhibition, but 1 mm-KCN restored the reductase activity quantitatively. The process of aerobic respiration rather than the oxygen molecule itself therefore inhibits tetrathionate reductase activity. Induced synthesis of reductase required anaerobic conditions. Cyanide and 2,4 DNP allowed anaerobic synthesis of reductase; aeration prevented it. This effect of oxygen was abolished neither by KCN nor by 2,4 DNP. Oxygen therefore represses the synthesis of tetrathionate reductase directly. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-62-1-95