Electron Transport and Cytochromes of Sub-Cellular Particles from Cauliflower Buds.

Abstract

The separation of 3 distinct types of particles from cauliflower bud homogenates is described. They are (1) a grey fibrous material, (2) brown-yellow particles with enzymatic activities and cytochrome components corresponding to those of mitochondria, and (3) light yellow particles occurring in fluffy and packed forms with enzymatic activities and cytochrome components associated with microsomes. The enzymatic activities investigated were: DPNH oxidation by oxygen, cytochrome c, and indophenol, oxidation of succinate by oxygen, and oxidation of reduced cytochrome c by oxygen. DPNH oxidase is concentrated in the mitochondrial particles and is inhibited by cyanide or antimycin whereas the DPNH cytochrome c reductase is concentrated in the light particles and is not sensitive to antimycin. The effect of phosphate on the requirement for cytochrome c for DPNH oxidase is described. DPNH oxidase activity declines on storage and is restored by addition of serum albumin. New DPNH and succinic cytochrome c reductase activity appears in medium particles treated with phosphate and ethanol.