Yuanhuacin A is a selective antagonist of phorbol ester receptor in protein kinase C

Sci China B. 1993 Jul;36(7):803-8.

Abstract

Protein kinase C with a molecular weight of 82 kD has been purified to electrophoresis homogeneous from rat brain through a series of chromatography columns including DE-52, Sepharose G-200 and phenyl-Sepharose. The enzyme possessed autophosphorylation activity. Yuanhuacin A inhibited the 3H-phorbol-12, 13-dibutyrate (3H-PdBu) binding of PKC with an IC50 value of 1.48 +/- 0.28 x 10(-8) mol/L when the concentration of 3H-PdBu was 1.5 x 10(-9) mol/L (Ki = 1.2 x 10(-8) mol/L). Yuanhuacin A inhibited the PdBu-stimulated PKC activity in the catalysis of the phosphorylation of Histone III-S with an IC50 of 2.82 +/- 0.37 x 10(-9) mol/L (PdBu = 10(-6) mol/L), while it had no effect on the basal and Ca(2+)-stimulated PKC activity in the same assay system. This result suggests that Yuanhuacin A is a selective antagonist of the phorbol ester receptor in protein kinase C.

MeSH terms

  • Animals
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Caenorhabditis elegans Proteins*
  • Carrier Proteins
  • Diterpenes / pharmacology*
  • Drugs, Chinese Herbal / chemistry
  • Male
  • Phorbol 12,13-Dibutyrate / metabolism
  • Phorbol 12,13-Dibutyrate / pharmacology
  • Protein Kinase C / antagonists & inhibitors*
  • Protein Kinase C / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Drug / antagonists & inhibitors*

Substances

  • Antineoplastic Agents, Phytogenic
  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • Diterpenes
  • Drugs, Chinese Herbal
  • Receptors, Drug
  • phorbol ester binding protein
  • phorbol ester receptor
  • Phorbol 12,13-Dibutyrate
  • Yuanhuacin
  • Protein Kinase C