Hemoglobin spacing in erythrocytes

Abstract

Summary 1. The gyration radius of hemoglobin in human erythrocytes was found to be 20–21 A. for normal cells and for cells subjected to osmotic swelling and shrinkage. 2. The low-angle scattering diagrams for normal, swollen, and shrunken human erythrocytes all showed a single diffraction ring; the scattering angle of the ring found for normal cells in isotonic saline corresponded to a value of 64 A. for the quotient λ/sin . 3. The quotient λ/sinvaried in a regular manner with the volume of the red cell. 4. The relationship between the distance λ/sinand the volume per red cell is consistent with the postulate that for normal or shrunken cells the intracellular hemoglobin exists in random orientation and random position except for noninterpenetrability. 5. This isotropic model for shrunken cells is in agreement with results obtained from solutions of human hemoglobin of comparable concentrations, although according to Riley and Herbert (17), the most concentrated solutions show a second diffraction ring which was not observed in our measurements on intracellular hemoglobin. 6. For swollen erythrocytes the values of λ/sinincrease with the cell volume more rapidly than would be predicted for simple isotropic expansion of a system in which the distance between neighboring molecules is related to λ/sinby a constant multiplicative factor k.