title: The transition from inhomogeneous to homogeneous kinetics in CO binding to myoglobin.
abstract: Heme proteins react inhomogeneously with ligands at cryogenic temperatures and homogeneously at room temperature. We have identified and characterized a transition from inhomogeneous to homogeneous behavior at intermediate temperatures in the time dependence of CO binding to horse myoglobin. The turnover is attributed to a functionally important tertiary protein relaxation process during which the barrier increases dynamically. This is verified by a combination of theory and multipulse measurements. A likely biological significance of this effect is in the autocatalysis of the ligand release process.
authors.affiliation: Department of Physical Chemistry, Hebrew University, Jerusalem, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Agmon
authors.forename: W
authors.initials: W
authors.lastname: Doster
authors.forename: F
authors.initials: F
authors.lastname: Post
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002248:Carbon Monoxide / Q000378:metabolism*; D002384:Catalysis; D006736:Horses; D066298:In Vitro Techniques; D007700:Kinetics; D008024:Ligands; D008956:Models, Chemical; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D013696:Temperature; D013816:Thermodynamics
chemical_list: D008024:Ligands; D009211:Myoglobin; D002248:Carbon Monoxide