title: Cobra polypeptide cytotoxin I and marine worm polypeptide cytotoxin A-IV are potent and selective inhibitors of phospholipid-sensitive Ca2+-dependent protein kinase.
abstract: The effects of a number of polypeptide cytotoxins and neurotoxins on various protein kinases were examined. It was found that cobra cytotoxin I and marine worm cytotoxin A-IV effectively and specifically inhibited phospholipid-sensitive Ca2+-dependent protein kinase (PL-Ca-PK) relative to myosin light chain kinase and cyclic nucleotide-dependent protein kinases. Inhibition of PL-Ca-PK by these cytotoxins could be overcome by phosphatidylserine. Neurotoxins, in comparison, were much less effective inhibitors. The present findings indicated that these polypeptide cytotoxins, unlike other agents reported to date, were selective inhibitors of PL-Ca-PK and could be used to differentiate Ca2+-dependent events regulated by phospholipid or calmodulin.
mesh_terms: D001514:Bee Venoms / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D003039:Cobra Neurotoxin Proteins / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D003603:Cytotoxins / Q000494:pharmacology*; D004546:Elapid Venoms / Q000494:pharmacology*; D007700:Kinetics; D008387:Marine Toxins / Q000494:pharmacology*; D009219:Myosin-Light-Chain Kinase; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors
chemical_list: D001514:Bee Venoms; C037374:Cerebratulus lacteus toxin A-IV; D003039:Cobra Neurotoxin Proteins; D003603:Cytotoxins; D004546:Elapid Venoms; D008387:Marine Toxins; D010718:Phosphatidylserines; D010743:Phospholipids; D047428:Protein Kinase Inhibitors; C037375:cobra cytotoxin I; D000242:Cyclic AMP; D009219:Myosin-Light-Chain Kinase; D006152:Cyclic GMP; D002118:Calcium