The correlation between drug binding to the human erythrocyte membrane and its hemolytic activity, determined by fluorescent probe techniques.

Cationic and anionic drugs which have hemolytic activities changed the fluorescence intensity of 1-anilino-8-naphthalene sulfonate (ANS) bound to the human erythrocyte ghost membrane. And there was a correlation between their hemolytic activities and fluorescence changes. Furthermore, ANS itself had a hemolytic activity. So it was indicated that ANS was a usefull compound to study hemolysis. The binding of ANS to the human erythrocyte ghost membrane and hemolysis by ANS were investigated with various concentration of ANS. The following results were revealed. (1) The human erythrocyte ghost membrane has two kinds of binding site for ANS. (2) The first site was already saturated by ANS before hemolysis occurred and the second site was about 50% saturated when hemolysis began. (3) The second site may play an important role in hemolysis.