Studies on the respiratory system of Aspergillus oryzae. V. Some properties of the respiratory system of mitochondria from mycelia grown in the presence of chloramphenicol.

Presence of chloramphenicol in the growth medium for mycelia of Aspergillus oryzae was without effect on the oxidative activity, respiratory control, or P/O ratio of isolated mitochondria. The mitochondria oxidized Krebs cycle intermediates even in the presence of cyanide at the concentration markedly inhibiting the normal mitochondrial oxidation. However, the P/O ratio during the mitochondrial oxidation decreased by about 1.0 on addition of cyanide. The c-type cytochromes, shown to occur in large amounts than in normal mitochondria (Wakiyama and Ogura, 1972), were suggested to act as electron carriers in this cyanide-resistant oxidation. A novel pigment, demonstrated only in the mitochondria prepared from chloramphenicol-treated mycelia by a CO-difference spectrum, was presumed to be the terminal oxidase of the respiration in the presence of cyanide.