It works to maintain low concentration levels of hydrogen peroxide, which is generated by the organism naturally through incomplete oxygen reduction.

When glucose levels in fast growing yeast strains are exhausted, the cells turn to respiration which raises the concentration of mitochondrial H2O2.

The mechanism involves ferrous cytochrome c (Cc) providing electrons for the Cc-CcP system to reduce hydrogen peroxide to water.

Much like catalase, the reaction of cytochrome c peroxidase proceeds through a three-step process, forming first a Compound I and then a Compound II intermediate: CCP in the resting state has a ferric heme, and, after the addition of two oxidizing equivalents from a hydroperoxide (usually hydrogen peroxide), it becomes oxidised to a formal oxidation state of +5 (FeV, commonly referred to as ferryl heme.

Compound I of CCP is fairly long-lived, decaying to CCP-compound II with a half-life at room temperature of 40 minutes to a couple hours.

Amino acid analyzer studies reveal presence of residues of Asp, Thr, Ser, Glu, Pro, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, Lys, His, Arg, Cys, and Trp in crystalline CCP.

[10] The enzyme contains a 68-residue sequence at the N-terminus of its monomeric protein, which targets it to the inter-membrane space of the mitochondria where it can the complex with cytochrome c and where it carries out its sensor, signaling and catalytic roles.