Isozyme-selective inhibitor of protein kinase C (PKC); competitively and reversibly inhibits PKCβI and PKCβII (IC50 values are 4.7 and 5.9 nM respectively). Selective for PKCβ over other PKC isozymes (IC50 values are 0.052, 0.25, 0.30, 0.36, 0.60 and >100 μM for PKCη, -δ, -γ, -α, -ε and -ζ respectively). Exhibits selectivity for PKC over other ATP-dependent kinases, including protein kinase A, casein kinase and src). MW (observed): 505.01.