antibiotic sf2370

K-252a is a staurosporine analog isolated from Nocardiopsis sp. soil fungi. K-252a inhibits protein kinase (IC50: 470 nM, 140 nM, 270 nM, and 1.7 nM for PKC, PKA, Ca2+ calmodulin-dependent kinase type II, and phosphorylase kinase, respectively).