FIG. 5.

Superoxide production by respiring V. cholerae cells in the presence and absence of a functional Na⁺-NQR. The reaction was started by mixing the cell suspension with cytochrome c in air-saturated buffer. The superoxide produced was reoxidized by cytochrome c in a nonenzymatic reaction. The reduction of cytochrome c was followed at 550 nm. Solid trace, with Na⁺-NQR; dashed trace, without Na⁺-NQR; dotted trace, with Na⁺-NQR and 1,615 U SOD.