Erythrocyte alterations in hemoglobin H disease

This study on erythrocytes in hemoglobin H (Hb H) disease reveals that unstable Hb H is bound to membranes to a greater extent, especially when it forms methemoglobin or is precipitated as inclusion body. The methemoglobin content of these erythrocytes is elevated in spite of a higher activity of NADH-methemoglobin reductase. The ATPase activity is doubled, and the ATP is presumably used for phosphorylation of membrane proteins, which leads to cross-linking of membrane proteins. This assumption could be supported by the observed decrease in non-electrolyte permeability, by increased binding of hemoglobin to the membrane and by polymerisation of membrane proteins detected by SDS-polyacrylamide gel electrophoresis. By means of electron microscopy, it could also be shown that the inclusion bodies are bound to the inner surface of membrane and cause its protrusion. This linkage might be responsible for the observed inhibition of the lateral movement of intramembrane particles.