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Decreased reduced glutathione and glutathione reductase activity in subjects with hemoglobin C
S Saad1, S I Salles, P E Velho
1Department of Clinical Medicine, State University of Campinas, UNICAMP-Brazil.
Insights
Red blood cell antioxidant enzymes like catalase and glutathione peroxidase are reduced in sickle cell anemia. Hemoglobin C disorders show lower reduced glutathione and glutathione reductase, potentially increasing red blood cell breakdown.
Area of Science:
- Hematology
- Biochemistry
- Red Blood Cell Metabolism
Background:
- Hemoglobin C (Hb C) disorders and sickle cell anemia (SCA) involve red blood cell abnormalities.
- Oxidative stress plays a role in the pathophysiology of hemoglobinopathies.
Purpose of the Study:
- To investigate erythrocyte antioxidant enzyme activities and glutathione levels in individuals with Hb C, Hb S, and combined Hb C/S conditions.
- To explore the relationship between these biochemical markers and red blood cell characteristics.
Main Methods:
- Quantification of erythrocyte catalase, reduced glutathione, glutathione peroxidase, and glutathione reductase.
- Comparison of enzyme activities and glutathione levels across control groups, Hb AC, Hb SC, Hb CC, and SCA patients.
Main Results:
- Decreased catalase and glutathione peroxidase activities were observed in sickle cell anemia.
- Significantly lower reduced glutathione and glutathione reductase activity were found in subjects with Hb C (Hb AC, Hb CC, Hb SC).
- Differences in red cell dehydration, potassium efflux, and Hb C binding to membrane proteins were noted.
Conclusions:
- Reduced glutathione and glutathione reductase may contribute to oxidative stress and hemolysis in Hb C disease.
- These biochemical alterations may be linked to specific red blood cell changes observed in Hb C and SCA.
Abstract:
Erythrocyte catalase, reduced glutathione, glutathione peroxidase and glutathione reductase were determined in 17 normal black controls, 8 subjects with Hb AC, 12 with Hb SC, 1 with Hb CC and 18 patients with sickle cell anemia. Catalase and glutathione peroxidase activities were decreased in sickle cell anemia. Reduced glutathione and glutathione reductase activity were significantly lower in subjects with Hb C (AC, CC, SC). Differences were observed between Hb C, Hb S and Hb A as regards red cell dehydration, intracellular crystallization, enhanced potassium efflux, an increased number of titratable SH groups in Hb C and the binding of Hb C to band 3 on the inner membrane surface. A decrease in reduced glutathione, probably due to inhibition or decreased synthesis of glutathione reductase, was also observed. All these factors may determine oxidation of Hb C, possibly contributing to the hemolysis in patients with Hb C disease.