Interaction of carbonyl cyanide 3-chlorophenylhydrazone with cytochrome c oxidase

Cytochrome c oxidase binds protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP) with high affinity. There are 1.46 high-affinity binding sites per cytochrome c oxidase for CCCP with dissociation constant 2.7 x 10(-7) mol/l. The bond between the CCCP and cytochrome c oxidase accomplishes through the group on cytochrome c oxidase with pKa 6.64 and is based on the electrostatic interaction. Interaction of CCCP with low-affinity binding sites of cytochrome c oxidase induces the shift of the anion CCCP spectrum to UV-region. The similar effect is characteristic for CCCP interaction with protons. Lipophilic non-dissociated derivative NCH3CCP is not binding to cytochrome c oxidase.