A new insight into mercurized hemoglobin aggregation mechanism

Area of Science:

• Biochemistry
• Protein Chemistry
• Biophysical Chemistry

Background:

• Oxyhemoglobin is the oxygen-carrying protein in red blood cells.
• Thiol groups are crucial for protein structure and function.
• Mercury compounds are known to interact with proteins.

Purpose of the Study:

• To investigate the coagulation of bovine oxyhemoglobin induced by mercuric acetate.
• To determine the relationship between mercury concentration and the rate of protein coagulation.
• To elucidate the binding sites and mechanisms involved in mercury-induced oxyhemoglobin coagulation.

Main Methods:

• Coagulation experiments were performed using bovine oxyhemoglobin in Tris-acetate buffer.
• Varying concentrations of mercuric acetate were used to study its effect on protein coagulation.
• Initial coagulation rates were measured and plotted against mercury-to-hemoglobin molar ratios.

Main Results:

• Coagulation rate showed a distinct break point at mercury concentrations sufficient to block all thiol groups.
• Increased mercury concentrations beyond thiol group saturation resulted in approximately quadratic enhancement of coagulation.
• Excess mercury ions appear to interact with specific binding sites near the dimer-dimer contact surfaces.

Conclusions:

• Mercuric acetate induces significant coagulation of bovine oxyhemoglobin.
• The protein coagulation effect is dependent on mercury concentration, with a notable increase beyond thiol group saturation.
• Binding of excess mercury ions to dimer-dimer interfaces likely contributes to the enhanced coagulation observed.