5'-Nucleotidase of L 1210 cells. Cytochemical and kinetic studies

The activity of 5'-nucleotidase in L 1210 leukaemia cells fixed in situ by glutaraldehyde was established by electron microscopic cytochemistry and biochemical assays. The enzyme activity is localized uniquely on the cell surface. In biochemical assays the time course of phosphate liberation by the suspension of glutaraldehyde fixed cells was linear up to 15 min incubation. The activity was proportional to the number of cells in the suspension, amounting of 0.019 units activity per 10(8) cells.