UCN-01 and UCN-02, new selective inhibitors of protein kinase C. II. Purification, physico-chemical properties, structural determination and biological activities

J Antibiot (Tokyo). 1989 Apr;42(4):571-6. doi: 10.7164/antibiotics.42.571.


A new inhibitor of protein kinase C (PKC), UCN-01, was isolated from the culture broth of Streptomyces sp. N-126. We have found that this strain also produces UCN-02 which is a stereoisomer of UCN-01. The inhibitors have the molecular formula C28H26N4O4 and have an indolo[2,3-alpha]carbazole chromophore. Their structures have been elucidated by mass and NMR spectra. UCN-01 has been shown to inhibit PKC and protein kinase A (PKA) with IC50 values of 0.0041 and 0.042 microM, respectively, and UCN-02 has been shown to inhibit PKC and PKA with IC50 values of 0.062 and 0.25 microM, respectively. UCN-01 and UCN-02 also showed the cytotoxic effect on the growth of HeLa S3 cells.

MeSH terms

  • Alkaloids / analysis
  • Alkaloids / isolation & purification*
  • Alkaloids / pharmacology
  • Bacteria / drug effects
  • Candida albicans / drug effects
  • Cell Division / drug effects
  • Chromatography, High Pressure Liquid
  • Chromatography, Thin Layer
  • HeLa Cells
  • Humans
  • Isomerism
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Protein Kinase C / antagonists & inhibitors*
  • Staurosporine


  • Alkaloids
  • 7-hydroxystaurosporine
  • Protein Kinase C
  • Staurosporine