High and Low Energy States of Cytochromes

Reversed electron transfer in submitochondrial particles causes the oxidation of cytochromes u3 + a and c, and reduction of cytochrome b upon addition of adenosine triphosphate, indicating a crossover point for the energy-linked reversal of electron transfer between cytochromes c and b. The cytochrome component designaged bbb5 is uniformly observed to show increased absorption in the low to high energy transition and vice versa. It is tentatively identified as a high energy intermediate in the energy transfer pathway. The 555 rnp compound is distinguished from cytochrome c by its presence in KCI-washed cytochrome c-deficient particles and by the lack of evidence for their interconvertibility. Its identification as a cytochrome of type b is conGamed.