the high potential side of the bell-shaped curve is monophasic ( em7 approximately 370 mv ) and is proposed to be due to reduction/oxidation of a copper center which , when in the cu ( ii ) form , is tightly spin-coupled to a heme , probably cytochrome o , resulting in a net even spin system and loss of the epr spectrum .
C0030012
reduction/oxidation
C0010798
cytochrome