Hirokazu Yamada

TL;DR: It was possible to picture simple models showing structural relations between five oxidation-reduction states of peroxidase.

TL;DR: Results support the previous conclusion that Kr represents a proton dissociation constant of a distal amino acid residue and that there is a strong hydrogen bonding between its base and the water oxygen atom as a sixth ligand in the ferric state of peroxidases.

TL;DR: It was concluded that the distinct shift of the pKa value in the case of peroxidase was attributable to the presence of a hydrogen bond between the sixth ligand and the distal base.

TL;DR: The present data support the previous conclusion that the pKa for ferroperoxidases, measured from small reversible changes in the absorption spectra, represents a proton dissociation constant of a distal amino acid residue and that there is hydrogen bonding between the residue and a ligand atom directly bound to the iron atom.

TL;DR: The stability of oxyperoxidases increased in the order meso- Δlog k 1 to ΔpK 3 was approximately 0.6 in the two series of isoenzyme preparations, horseradish peroxidase A and (B + C), where k 1 and pK 3 represent a rate constant for conversion from an oxyperoxideidase to the ferric enzyme and a measure of basicity of pyrrole nitrogen of substituted deuterohemes, respectively as discussed by the authors.