The autoxidation of horse hemoglobin: the effect of glutathione.

The research article discusses the role of reduced glutathione in inhibiting the autoxidation process of horse hemoglobin and emphasizes on the potential mechanisms involved in this process.

Role of Glutathione in Inhibiting Autoxidation of Hemoglobin

• The study showed that reduced glutathione, present within the red blood cells, significantly inhibited the autoxidation process of horse hemoglobin. Autoxidation is a natural oxidizing process that damages the structure and function of hemoglobin, a protein responsible for carrying oxygen in the blood.
• The researchers also observed that not only reduced glutathione but also higher concentrations of oxidized glutathione could stabilize hemoglobin, suggesting a broader role of glutathione in hemoglobin stability.

Mechanism of Hemoglobin Stabilization by Glutathione

• The stabilization effect of oxidized glutathione on hemoglobin was theorized to involve the formation of a mixed disulfide bond with the β-93 sulfhydryl groups present on the hemoglobin. Sulfhydryl groups are reactive sulfur-containing entities found in proteins and can participate in a variety of molecular interactions.
• The study found a similar stabilization effect with two other compounds, N-ethyl-maleimide and HgCl2, which also interact with the sulfhydryl groups, confirming the essential role of these groups in hemoglobin stability.

Role of Reduced Glutathione in Hemoglobin Stabilization

• Interestingly, the apparent stabilization effect of reduced glutathione was seen to be due to its ability to reduce ferrihemoglobin, a form of hemoglobin that is produced during the autoxidation process.
• The researchers proposed that reduced glutathione might also indirectly interact with the β-93 sulfhydryl groups on the hemoglobin, further contributing to its stabilization.
• Evidence was provided to suggest a mechanism where this reaction is coupled with the one-electron reduction of ferrihemoglobin by reduced glutathione, although this aspect requires further investigation.