Age-dependent separation of erythrocytes by preparative electrophoresis

Human and rat erythrocytes have been fractionated according to charge by density-gradient electrophoresis. Some 1 to 2 ml, or about 10(10) of packed cells, can be electrophoresed up a stabilizing sucrose gradient, and require 3 to 4 hr for effective fractionation. The fastest migrating erythrocytes were the least fragile, were larger, incorporated the most 59Fe, and contained more glucose 6-phosphate dehydrogenase activity. These findings are consistent with the most negatively charged erythrocytes being the youngest cells, agreeing with other separative procedures based on density, phase partitioning, or serial osmotic hemolysis.