2,6-Diamino-N-([1-(1-oxotridecyl)-2-piperidinyl] methyl)hexanamide (NPC 15437): a novel inhibitor of protein kinase C interacting at the regulatory domain.
NPC 15437 is a prototype member of a new class of synthetically derived protein kinase C (PKC) inhibitors. PKC activity and binding of phorbol ester to the enzyme were inhibited by NPC 15437, with IC50 values of 19 +/- 2 microM and 23 +/- 4 microM, respectively. No inhibition of cAMP-dependent or calcium/calmodulin-dependent protein kinases was observed at concentrations of NPC 15437 up to 300 microM. To investigate the mechanism by which NPC 15437 exerts its effects, a kinetic analysis of the inhibition with respect to three activators of the enzyme, phosphatidylserine, calcium, and phorbol ester, was performed. NPC 15437 was a competitive inhibitor of the activation of PKC by phorbol ester (Ki = 5 +/- 3 microM). Stimulation of PKC alpha by phosphatidylserine was competitively inhibited by NPC 15437 (Ki = 12 +/- 4 microM). The inhibition was mixed with respect to activation by calcium. These results suggest that NPC 15437 is a selective inhibitor of PKC, interacting at the regulatory region of the enzyme. NPC 15437 inhibited PKC in intact cells, dose-dependently antagonizing the phorbol ester-induced phosphorylation of a 47-kDa protein in human platelets.
Sullivan
J P
JP
Nova Pharmaceutical Corporation, Baltimore, Maryland 21224.
Connor
J R
JR
Shearer
B G
BG
Burch
R M
RM
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000187:drug effects; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000187:drug effects; D051381:Rats
D010880:Piperidines; D047428:Protein Kinase Inhibitors; C069701:NPC 15437; D011494:Protein Kinases; D011493:Protein Kinase C; D009219:Myosin-Light-Chain Kinase