A selective and potent ROCK inhibitor (IC₅₀ = 11.8 nM for ROCK-II); poorly inhibits CaMKII, protein kinase G, and Aurora A (IC₅₀ = 2.57, 2.35, and 3.26 μM, respectively) as well as PKA or PKC (IC₅₀ ≥ 10 μM for each).