Cyanide Resistance in Achromobacter I. Induced Formation of Cytochrome a 2 and Its Role in Cyanide-Resistant Respiration

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Abstract
Arima, Kei (University of Tokyo, Tokyo, Japan), and Tetuo Oka . Cyanide resistance in Achromobacter . I. Induced formation of cytochrome a 2 and its role in cyanide-resistant respiration. J. Bacteriol. 90: 734–743. 1965.—By following the cytochrome concentrations during the growth cycle and under various conditions (aerobic, aerobic plus KCN, reduced aeration, anaerobic plus NaNO 3 ) in Achromobacter strain D, a close relationship between the formation of cytochrome a 2 (and a 1 ) and the difficulty of oxygen utilization was demonstrated. Cytochrome o , which was the only oxidase found in aerobic log-phase cells, was present in bacterial cells grown under various conditions; the amount present had no relation to the degree of cyanide resistance. On the other hand, cytochrome a 2 (and a 1 ) was inducible, and a close relation was observed between the amount of cytochrome and resistance to cyanide. Spectrophotometric observations indicated that, among the cytochromes present in resistant cells, cytochrome a 2 could be oxidized most easily in the presence of cyanide and that cytochrome b 1 could be oxidized without the oxidation of cytochrome a 1 . We concluded that cytochrome a 2 is a cyanide-resistant oxidase capable of catalyzing the oxidation of cytochromes in the presence of cyanide. Cytochrome a 2 is also resistant to azide, an inhibitor of cytochrome oxidase.