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Extraction of erythrocyte membrane proteins by sulfhydryl inhibitors
Abstract:
Human red cell membrane proteins were extracted by incubation of the ghost with hypotonic phosphate buffer (pH 7.4), N-ethylmaleimide and p-hydroxy-mercuribenzoate. In paroxysmal nocturnal hemoglobinuria (PNH), hereditary spherocytosis (HS) and hereditary elliptocytosis, the amount of proteins extracted by these procedures was significantly less than the amount extractable from the ghost of normal and aplastic anemia red cells. Polypeptide patterns of red cell membranes in these hematological disorders were essentially similar to those of normal ghosts. Analysis of the supernatant by SDS polyacrylamide gel electrophoresis revealed that this reduction was mainly due to the reduced amount of peripheral proteins extracted. The extraction of peripheral proteins by sulfhydryl reagents was accompanied by shape changes resulting in the formation of membrane vesicles, suggesting an important role of peripheral proteins in the maintenance of ghost shape. It is also suggested that qualitative abnormalities of peripheral proteins such as altered reactivity to sulfhydryl reagents and/or strong binding to the membrane are present in PNH, HS and hereditary elliptocytosis red cells.
Insights
Red blood cell membrane proteins are less extractable in certain blood disorders like paroxysmal nocturnal hemoglobinuria (PNH) and hereditary spherocytosis (HS). This reduction, primarily in peripheral proteins, suggests their crucial role in maintaining red cell shape and potential abnormalities in these conditions.
Area of Science:
- Hematology
- Biochemistry
- Cell Biology
Background:
- Red blood cell membrane proteins are crucial for maintaining cell structure and function.
- Disorders like paroxysmal nocturnal hemoglobinuria (PNH), hereditary spherocytosis (HS), and hereditary elliptocytosis involve red blood cell abnormalities.
- Peripheral proteins play a significant role in the structural integrity of the red blood cell membrane.
Purpose of the Study:
- To investigate the extractability of red blood cell membrane proteins in patients with PNH, HS, and hereditary elliptocytosis.
- To determine the role of peripheral proteins in maintaining red blood cell membrane shape.
- To identify potential qualitative abnormalities in peripheral proteins in these hematological disorders.
Main Methods:
- Extraction of red cell membrane proteins using hypotonic phosphate buffer and sulfhydryl reagents (N-ethylmaleimide, p-hydroxy-mercuribenzoate).
- Analysis of extracted proteins and supernatant using SDS polyacrylamide gel electrophoresis.
- Observation of red blood cell ghost shape changes during protein extraction.
Main Results:
- Significantly reduced amounts of extractable proteins were observed in PNH, HS, and hereditary elliptocytosis red cells compared to normal and aplastic anemia red cells.
- The reduction was primarily attributed to a decreased amount of extractable peripheral proteins.
- Extraction of peripheral proteins with sulfhydryl reagents induced shape changes and membrane vesicle formation.
Conclusions:
- Peripheral proteins are essential for maintaining the shape of red blood cell ghosts.
- Patients with PNH, HS, and hereditary elliptocytosis may have qualitative abnormalities in their peripheral proteins, affecting their reactivity to sulfhydryl reagents or their binding to the membrane.
- These findings suggest a potential link between peripheral protein abnormalities and the pathogenesis of these red blood cell disorders.