Possible involvement of superoxide anion in the induction of cyanide‐resistant respiration in Hansenula anomala

Abstract

A chemiluminescence study showed that Q_i site inhibitors such as antimycin A induce O₂ ⁻ generation in respiring cyanide‐sensitive mitochondria from the yeast, Hansenula anomala. The O₂ ⁻ generation was suppressed by radical scavengers such as flavone, butylated hydroxyanisole, and Co₀. Induction of cyanide‐resistant respiration in H. anomala cells by Q_i site inhibitors was also inhibited by these radical scavengers. Furthermore, antimycin A‐induced synthesis of the mitochondrial 36‐kDa protein, which is thought to be the alternative oxidase functional in the cyanide‐resistant respiratory pathway, was abolished by the addition of flavone. These observations suggest that O₂ ⁻ is somehow involved in the induction of cyanide‐resistant respiration.