| Popis: |
The absorption of RNase by ascites tumor cells and bone marrow cells was followed by measuring enzymic activity and the radioactivity of cell suspensions incubated in the presence of enzyme labeled with 1311. Experiments indicated that the enzyme penetrated into the interior of the cells and that the rate of penetration depended on the concentration of RNase in the medium. The penetration of the enzyme into ascites tumor cells was not affected by temperature as long as the concentration of RNase in the external medium did not exceed a certain threshold value. These facts suggested that several mechanisms- diffusion, membrane activity, pinocytosis-all differentially influenced by temperature, facilitate the penetration of RNase into the cell. In the light of these new results, the effects of RNase on the metabolism of normal cancerous cells are discussed. |
