FIG. 4.

Dependence of protein 1 phosphorylation by [β-³²P]ATP on the concentration of ATP. Note that a constant amount of radioactivity (50,000 Bq per 50 μl assay mixture) was applied, i.e., the specific radioactivity of ATP decreased with increasing ATP concentration. The assay was carried out as described in the legend for Fig. 3 but using various ATP concentrations. Double determination, a deviation of ±5%.