Spectroscopic evidence of the participation of the cytochrome-cytochrome oxidase system in the active transport of salts.

Abstract

WITH a recording microspectrophotometer of special construction, the absorption spectrum of a bundle of twenty to forty roots of wheat shows distinct bands of cytochrome c (Fig. 1). The bands of the cytochromes b and a + a3 are also recognized as elevations of the curve. The spectrum is calculated as the relation between the transparency of the roots in distilled water and the transparency after shifting over the medium to 0.001 M hydrogen cyanide, the cytochromes being partly in the oxidized state in the untreated roots. The reduction in hydrogen cyanide is due to the blocking of the cytochrome oxidase at still operating dehydro-genases. With carbon monoxide a broadening of the γ-band of cytochrome b is observed. Calculated from the absorption at λ 550 mµ the roots contain approximately 4 mgm. cytochrome c per kgm. fresh weight. The cytochrome system is present at all lengths of the roots of two–three weeks old seedlings. Also single roots of maize show similar spectra.