“…The Raman spectrum of a protein-free ferrous heme was measured first in the present study although the ferric one was reported previously. 15 The Raman bands at 1359, 1492, 1537, and 1617 cm""1 of Fe2+(PP)(Im)2 show high wavenumber shift to 1374, 1503,1562, and 1638 cm-1 in Fe3+(PP)(Im)2, in good agreement with the corresponding wavenumber shifts (from 2631 1361, 1493, 1538, and 1617 cm""1 to 1375, 1505, 1563, and 1639 cm-1) observed for cytochrome 65. 21 The corresponding wavenumber shifts due to the oxidation of the iron ion for Fe(OEP)(L)2 and Fe(PPME)(L)2 (PPME = protoporphyrin dimethyl ester) are compared with those of Fe-(PP)(Im)2 in Table II.…”