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Title:Pressure and temperature dependence of myoglobin kinetics
Author(s):Alberding, Neil Arnold
Doctoral Committee Chair(s):Frauenfelder, Hans
Department / Program:Physics
Subject(s):myoglobin kinetics
protein kinetics
recombination kinetics
carbon monoxide
Abstract:Recombination kinetics of carbon monoxide to myoglobin and protoheme are measured from 0.1 MPa to 190 MPa (1 bar to 1.9 kbar) at temperatures from 290K to 60K using flash photolysis. The role of the protein structure is elucidated by comparison of myoglobin kinetics with those of protoheme whose active center is similar to myoglobin's but is not enclosed within a globular protein structure. The results are interpreted in terms of sequential Gibbs energy barriers along the ligand's reaction coordinate between the solvent and the binding site. Entropies and enthalpies of activation for each reaction step are extracted using this model. A nonrelaxed distribution of conformational states is used to explain the process below 200K. Tne distribution of activation enthalpies is derived from the data at high and low pressures. We determine that the influence of pressure on reaction kinetics below 200K is due to structural changes of the protein. The kinetics at higher temperatures indicate that the barriers to recombination caused by the protein structure are lessened at high pressure whereas the barrier at the solvent-protein boundary is increased by pressure.
Issue Date:1978
Genre:Dissertation / Thesis
Rights Information:1978 Neil Arnold Alberding
Date Available in IDEALS:2011-06-30
Identifier in Online Catalog:311920

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