A new inhibitor of protein kinase C, RK-286C (4'-demethylamino-4'-hydroxystaurosporine). I. Screening, taxonomy, fermentation and biological activity.

In the course of our screening program using a bleb-forming assay, a new inhibitor of protein kinase C (PKC) was found in the fermentation of a streptomycete. The inhibitor, RK-286C (4'-demethylamino-4'-hydroxystaurosporine), inhibited the morphological change of K562 cells, a human chronic erythroleukemia cell, induced by phorbol 12,13-dibutylate at the concentration of 3 microM. The same concentration of the compound inhibited the activity of PKC in vitro and the aggregation of rabbit platelets induced by collagen and arachidonic acid.