Influence of the albumin concentration and temperature on the lysis of human erythrocytes by sodium dodecyl sulfate

The stability of human erythrocytes to sodium dodecyl sulfate (SDS) was assessed spectrophotometrically in the presence of different concentrations of bovine serum albumin (BSA) and at different temperatures (27-45 A degrees C). The absorbance at 540 nm (A (540) ) was correlated with the SDS concentration by sigmoidal regression based on the Boltzmann equation. Erythrocyte stability was characterized on the basis of the SDS concentration that induces hemolysis in 50% of the cells (D (50) ). Progressive increases in the albumin concentration led to increases in the D (50) value. The protective effect of BSA against SDS-induced hemolysis was attributed to the binding of the surfactant to the hydrophobic binding sites of this protein. The D (50) values decreased sigmoidally with an increase in the temperature. This trend, which could not be explained by changes in the spectral properties of hemoglobin, maybe due to heterogeneity in the erythrocyte population.