A comparison of the iron bonding in anhydrohemoglobin and anhydromyoglobin.

Mössbauer effect measurements show that the ferrous ions in dehydrated deoxymyoglobin are in the high spin state while those in dehydrated deoxyhemoglobin (AHb) are equally distributed between high and low spin states. It is concluded that the two spin states present in AHb are associated with the iron site difference of the alpha- and beta-chains.

Spin States of divalent iron in anhydrohemoglobin.

Mössbauer spectra of anhydrohemoglobin establish the existence of two ferrous iron spin states in anhydrohemoglobin. Magnetic susceptibility measurements show that anhydrohemoglobin is paramagnetic and has an effective magnetic moment per iron atom of 3.5+/-0.1mu(B) at low temperatures. In conjunction with the susceptibility results, the Mössbauer spectra indicate that the iron in anhydrohemoglobin is distributed between high and low spin states in roughly equal amounts.