Electrophoretic mobility of mouse cells and homologous isolated nuclei

The electrophoretic mobilities of Ehrlich ascites, sarcoma 37 ascites, mouse liver cells and their isolated nuclei were measured under similar environmental conditions. No differences in mobility were detected between cells and homologous nuclei from the same cell population and it was concluded that their surface charge densities were probably the same. The effect of neuraminidase on Ehrlich ascites and liver cells and nuclei was also determined; neuraminidase reduced the mobility of Ehrlich ascites cell nuclei as well as cells. The reduction in mobility of cells and nuclei prepared by a sucrose method was the same; however, the reduction in mobility of citric acid prepared nuclei was less than that of citric acid treated cells. The reduction in mobility of both liver cells and nuclei was small or insignificant. It is suggested that although cells and nuclei have similar electrophoretic mobilities, possibly different groups contribute to their surface charge.