A study of the cytochrome system and some other aspects of the respiration of Aerobacter aerogenes

Abstract

A. aerogenes grown in nutrient broth shows the absorption bands of reduced cytochrome a2, 630u; a1, 590 m[mu]; and b1, 560 m[mu]. On oxidation, a1 and b1 disappear, while a2 shifts from 630 to 645 m[mu]. The concn. of a2 is very high and a2 acts as cytochrome oxidase. In Aerobacter grown in metal-deficient medium, a2 becomes hardly detectable but respiration with glucose is not affected. Azide does not combine with any of the cytochrome components; it increases the O2 uptake, glucose utilization, CO2 and pyruvate production, an anaerobic methylene blue reduction, with glucose, but not with galactose and fructose, and inhibits O2 uptake and methylene blue reduction with succinate or acetate. Addition of Fe to the metal-deficient medium of metal-deficient cells restores the O2 uptake and methylene-blue reduction to that of normal cells. Octyl alcohol completely inhibits O2 uptake with glucose, increases methylene blue reduction and slows rate of reduction of cytochrome components. At 0[degree] it has no effect on O2 uptake and reduction of cytochrome but still increases the rate of methylene blue reduction.