Electric-field-induced fusion of enzyme-treated human red cells: kinetics of intermembrane protein exchange.

Fusion of neuraminidase or trypsin pretreated human erythrocytes and untreated cells was performed. The obtained doublets had a permanent dipole moment which disappeared as a function of time. Since the dipole moment disappearance is due to protein interdiffusion the lateral diffusion constant may be determined. This was performed by fixing fused cells in different time intervals following the electric pulse and by measuring the reorientation of fixed cell doublets in a static electric field. A surprisingly high diffusion constant was obtained, about 3 X 10(-9) cm2/s. A delay in interdiffusion kinetics was observed in neuraminidase treated cells; this may be due to a restricted growth of the fusion site perimeter. Our data demonstrate that protease treatment promotes electric-field-induced cell-to-cell fusion.