The Kinetic Inversion Problem in Ligand‐Binding Heme Proteins

For a two‐dimensional potential of intersecting parabolic bowls, we obtain an analytical approximation for the survival probability in the limit that the reactive mode is diffusive and the perpendicular protein mode frozen. The approximation is used in an automated computer algorithm for determining the parameters of the potential. Using this program, we are able to obtain a reasonably good fit to the low‐ temperature data of CO binding to horse myoglobin. We find, however, that features of the potential such as the saddle‐point energy and the effective barrier, expected to dictate the high‐temperature kinetics, are not uniquely determined for this potential from fitting the low‐temperature data.