Heme-linked properties of Pseudomonas cytochrome c peroxidase. Evidence for non-equivalence of the hemes.
Pseudomonas cytochrome c peroxidase contains two hemes, one of which is shown to be in low-spin and one in high-spin state. The ferric enzyme reveals absorption maxima at 640 and 705 nm. The alkaline transition of these bands indicates the sixth iron-binding ligand of the low-spin and high-spin heme to be, respectively, a methionyl residue and a water molecule. The high-spin heme reacts with hydrogen peroxide to form a ferryl structure, which is the reactive intermediate in the peroxidatic reaction. The ferrous enzyme binds carbon monoxide in a 1:1 molar ratio, whereas the ferric form is unreactive towards small anionic ligands like F- and CN-. On this basis the peroxidase may also be classified as a cytochrome cc'.
D002248:Carbon Monoxide; D003578:Cytochrome-c Peroxidase; D005295:Ferrocyanides; D006418:Heme; D006861:Hydrogen Peroxide; D007700:Kinetics; D008024:Ligands; D010084:Oxidation-Reduction; D010544:Peroxidases; D011487:Protein Conformation; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D013053:Spectrophotometry
D005295:Ferrocyanides; D008024:Ligands; D006418:Heme; D002248:Carbon Monoxide; D006861:Hydrogen Peroxide; D010544:Peroxidases; D003578:Cytochrome-c Peroxidase