[Visible spectral character of heme iron in biomacromolecules]

The visible spectra of hemin, hemoglobin, cytochrome C, peroxidase and so on were compared and analyzed based on the experiments. The fifth and sixth coordinate bond of heme iron in biomacromolecule may affect their visible spectra in peak form and position. The sixth coordinate bond of ferrous heme iron that is in low-spin displays two peaks, and in high-spin, ferrous heme without the sixth coordinate bond of iron gives only one peak. That is in favor of our understanding of the character, function and stability of heme-containing biomacromolecule. The spectral character of iron coordinate bonds is due to that these coordinate bonds change the iron position related to porphyrin plane and its spin state.