Table 1.

Single Substrate Assay: Compound IC₅₀ Values (uM)

Compound	phospho-MK2	phospho-ATF2	substrate selectivity*
SD-0006	0.11 ± 1.2	0.35 ± 1.1	3.3
BIRB 796	7.75 ± 1.3	0.92 ± 1.1	0.12
CMPD1	23.4 ± 1.9	>400**	>17

IC₅₀'s are shown ± standard error.

*Substrate Selectivity is defined as a relative measure between inhibiting phospho-ATF2 and phospho-MK2 = (ATF2 IC₅₀)/(MK2 IC₅₀). This quantity is distinct and separable from a compound's potency.

**CMPD1 is unable to completely inhibit phospho-ATF2 within its solubility limits.