The Two Forms of the Imidazole Hemochrome of Heme a

This is the authors' abstract. We don't add key points for this paper.

Two forms of the imidazole hemochrome of heme a have been found. One of these, referred to as the weakly interacting form, has typical hemochrome spectra and properties, but the other, the strongly interacting form, is abnormal. The latter form does not react with sodium borohydride or carbon monoxide, but these reactivities may be restored by treatment with sodium dodecyl sulfate. The two forms exist as a mixture, and are interconvertible under the proper conditions. Complete conversion to the weakly interacting form can be attained, but not complete conversion to the other form. Heme-heme interaction is held to be responsible for these unusual properties. The ferrous absorption bands of the weakly interacting form are at 591, 513, and 437 mµ, while those of the strongly interacting form are at 594, 513, and 453 mµ. The strongly interacting form is proposed as a new model for cytochrome a.