Spectroelectrochemistry of hemoglobin: A comparative analysis of dolphin hemoglobin (dHb) and human hemoglobin (HbA0)

INOR 478

S. Dhungana, dhungana@chem.duke.edu, Chemistry Department, Duke University, Box 90346, Durham, NC 27708-0346, C. Bonaventura, Duke University Marine Laboratory, Nicholas School of the Environment, Beaufort, NC 28516, and Alvin L. Crumbliss, alc@chem.duke.edu, Department of Chemistry, Duke University, Durham, NC 27708.
Spectroelectrochemistry offers an opportunity to probe the redox potential and level of electron transfer cooperativity in various hemoglobins (Hbs) through analysis of the resulting Nernst plots, and is readily utilized to study environmental effects such as pH and exogenous ions on these parameters. The redox behavior of dolphin hemoglobin (dHb) and human hemoglobin (HbA0) were investigated with the objective of understanding the influence of globin structure on heme redox potential. Our results indicate similar redox potentials for the two hemoglobins at pH 7.5; however the redox potential of dHb is shifted positive compared to that of HbA0 at pH 7.0. The sensitivity of the redox potential of dHb to pH suggests a pronounced Bohr effect in dHb. Anion effects on the electron affinity of the active-site iron atoms and the cooperativity of electron transfer between the subunits were also investigated. Redox shifts upon addition of anionic allosteric effectors were found to be similar for the two hemoglobins, despite significant differences in their affinity for O2.
 

Electrochemistry
2:00 PM-5:00 PM, Monday, 11 September 2006 Moscone Center -- Room 307, Oral

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006