| Abstract: | Ribonuclease was shown to reduce the electrophoretic mobility of a line of cultured mammalian cells (RPMI no. 41), and Ehrlich ascites tumour cells. No reduction was detected in the case of human, mouse or embryonic chick erythrocytes. These data, taken with the various controls, support the hypothesis that RNA is a structural component of the peripheries of two types of cells, but not of erythrocytes from three species. Calcium-binding was studied in RPMI no. 41 cells, Ehrlich ascites tumour cells, and human and mouse eryhrocytes, by measurement of reduction in cellular electrophoretic mobility in suspending solutions containing various concentrations of calcium chloride. The effect of treating cells with neuraminidase and/or ribonuclease on calcium-binding was also studied. The results suggest that less calcium binds to the carboxyl groups of peripheral sialic acids than to the phosphates of peripheral, structural RNA. However, calcium apparently binds most avidly to as yet unidentified anionic sites. |
