[Autooxidation and oxygenation of human hemoglobin]

Area of Science:

• Biochemistry
• Physical Chemistry

Context:

• Hemoglobin's reversible oxygen binding is crucial for life.
• Hemoglobin's nonreversible autoxidation contributes to oxidative stress.

Purpose:

• To investigate the activation energies of hemoglobin's oxygen binding and autoxidation.
• To examine the effects of pyridoxal phosphate, pH, and alcohols on these processes.

Summary:

• Pyridoxal phosphate reduced hemoglobin's oxygen affinity and cooperativity but increased autoxidation rates.
• Autoxidation accelerated at lower pH and in the presence of alcohols, suggesting distinct mechanisms.
• Activation energies for oxygen binding (26 kJ/mol) and autoxidation (120 kJ/mol) were determined.

Impact:

• Provides insights into hemoglobin's functional dynamics and susceptibility to oxidative damage.
• Highlights potential therapeutic targets for modulating hemoglobin function and redox state.