1.11.1.5 Iron heme prosthetic group 394608, 394612, 394613, 394614, 394628, 394629 1.11.1.5 Fe two haemes per monomer, pyridine haemochrome spectra 394632 1.11.1.5 Ca2+ pre-incubation with the cation has no effect on activity 659522 1.11.1.5 additional information catalytic center activity increases with ionic strength in the case of cytochrome c551, with horse heart cytochrome c, the catalytic center activity decreases exponentially 659522 1.11.1.5 Fe two haeme groups 663918 1.11.1.5 Fe 2 hemes 663999 1.11.1.5 Fe 2 hemes per subunit 664002 1.11.1.5 Fe static titration of ferric cytochrome c peroxidase with reduced azurin shows that only one of the two hemes in the enzyme seems to be readily reduced 665456 1.11.1.5 Ca2+ a single, tightly bound, Ca2+ ion at the domain interface of both the fully oxidized and mixed-valence forms of the enzyme is absolutely required for catalytic activity, reduction of the electron-transferring (high-potential) heme in the presence of Ca2+ ions triggers substantial structural rearrangements around the active-site (low-potential) heme to allow substrate binding and catalysis 685208 1.11.1.5 Ca2+ with added Ca2+, the peroxidatic heme is five-coordinate high-spin and active 685251