Potent, ATP-competitive protein kinase C (PKC) inhibitor (IC50 = 0.01 μM). Displays selectivity for PKC over protein kinase A (PKA) and phosphorylase kinase (PK) (IC50 values are 0.75 and 2μM for PK and PKA respectively). Also displays potent, noncompetitive antagonism at nicotinic cholinergic receptors (IC50 ~ 0.03 μM for inhibition of catecholamine secretion in nicotine-stimulated PC-12 cells). Purity 97%. MW (observed): 438.52