Figure 4.

Autoradiograph of the MTR kinase assay with increasing concentrations of substrate. The assay was carried out for 90 min at 37°C with cell-free extracts of wild type (see Materials and Methods). Lane 1 corresponds to [³²P]ATP as standard; lanes 2: no MTR added; lanes 3, 4, 5, 6 and 7: reaction performed with increasing concentrations of MTR (20, 40, 80, 160 and 320 μM, respectively). Saturation is observed at 160 μM.