FIG. 4.

Sensitivity of S. solfataricus protein kinase to inhibitors of eukaryotic protein kinases. The DE-52 fraction, 3.2 μg of protein, was assayed for protein kinase activity toward the MLC peptide under standard conditions with the exception that, where indicated, the following compounds were present at the concentrations indicated on the ordinate: H7, genistein, and ML-9. Shown is activity relative to that measured in the absence of inhibitor, 4.0 pmol/min/mg, which was set equal to 100%.