The Pfam entry does not include all Prosite members. The cytochrome 556 and cytochrome c' families are not included. All these are now in a new clan together. The C-terminus of DUF989, Pfam:PF06181, has now been merged into this family.
Cytochrome c peroxidase (CCP) catalyses the reduction of hydrogen peroxide to water, an important step in the cellular detoxification process. Two cytochrome c molecules serve as the electron donors. Di-heme CCPs are found in bacteria including Pseudomonas aeruginosa, Paracoccus denitrificans and Pseudomonas nautica. The overall reaction is: 2 cyt c (Fe2+) + H2O2 -> 2 cyt c (Fe3+) + 2 H2O. The enzyme has two heme cofactors, referred to as high and low potential hemes (HP heme and LP heme), located in the C and N terminal domains respectively. The enzyme requires Ca2+ for activation; calcium causes structural changes and removal of a heme ligand, allowing peroxide approach.
