The mechanism for the reversible oxygen addition to heme. A theoretical CASPT2 study.

By performing CASPT2 calculations, the lowest energy pathway for oxygen addition to an isolated heme center of a heme-protein is evaluated and found to be reversible (the oxyheme compound is just 14.9 kcal mol(-1) more stable than the deoxyheme + O(2) reactants, and the energy barriers to dissociation are even smaller).

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