Abstract
Reduced-minus-oxidized difference spectra of sonically treated virulent T. pallidum disclosed cytochromes of the b and c types and large amounts of flavoprotein. Difference spectra of the CO-binding pigment identified cytochrome o as the terminal oxidase. Physiological reduction of the cytochromes indicated that the cytochrome system was functional and established the capability of T. pallidum for aerobic respiration. The potential significance of these findings is discussed.