K252b (99570-78-2) is a potent pan-specific protein kinase inhibitor: PKA (Ki = 20 nM), PKG (Ki = 100 nM)1 as well as other kinases. Cell impermeable2.
1) Kase et al. (1987), K252 compounds, novel and potent inhibitors of protein kinase C and cyclic nucleotide-dependent protein kinases; Biochem. Biophys. Res. Commun., 142 436
2) Makino et al. (2012), Inhibition of uterine sarcoma cell growth through suppression of endogenous tyrosine kinase B signaling; PLoS One, 7 e41049