Pressure and temperature dependence of myoglobin kinetics

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Alberding, Neil Arnold

Contributors dc:contributor

• Frauenfelder, Hans

• myoglobin kinetics
• protein kinetics
• recombination kinetics
• carbon monoxide
• protoheme

Statement dc:rights

• 1978 Neil Arnold Alberding

Language dc:language

en

Identifier

311920

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25606