Cytochrome c2 is found mainly in purple, non-sulfur, photosynthetic bacteria where it functions as the electron donor to the oxidized bacteriochlorophyll in the photophosphorylation pathway. However, it may also have a role in the respiratory chain and is found in some non-photosynthetic bacteria. Binds 1 heme c group covalently per subunit. Belongs to the cytochrome c family. Approximately 30% of the residue corresponding to Tyr-62 is present as Phe, suggesting there may be more than 1 gene for this protein in this organism.