Skepinone-L (CBS3830) is a selective p38 mitogen-activated protein kinase inhibitor.

Skepinone-L shows concentration-dependent inhibition of HSP27 (Ser82) phosphorylation through the p38 MAPK pathway with a cellular IC50 of approximately 25 nM, and also reduces concentrations of TNF-α, IL-1β and IL-10, regulated by p38 MAPK, with IC50 ranging from 30 to 50 nM . [1] Skepinone-L (1 μM) abrogates the phosphorylation of platelet p38 MAPK substrate Hsp27 activated by stimulation with CRP, thrombin or thromboxane A2 analogue U-46619, and impairs platelet secretion and aggregation. [2]

In vivo, skepinone-L inhibits Gal/ LPS-induced TNF-α release by 77%. [1]

CDK1 kinase activity is tested by the CDK1/cyclin B complex purified from baculovirus to phosphorylate a biotinylated peptide substrate containing the consensus phosphorylation site for histone H1, which is phosphorylated in vivo by CDK1. Inhibition of CDK1 activity is measured by observing a decreased amount of 33P-γ-ATP incorporation into the immobilized substrate in streptavidin-coated 96-well scintillating microplates. CDK1 enzyme is diluted in 50 mM Tris-HCl (pH 8), 10 mM MgCl2, 0.1 mM Na3VO4, 1 mM DTT, 1% DMSO, 0.25 μM peptide, 0.1 μCi per well 33P-γ-ATP, and 5 μM ATP in the presence or absence of various concentrations of JNJ-7706621 and incubated at 30 °C for 1 hour. The reaction is terminated by washing with PBS containing 100 mM EDTA and plates are counted in a scintillation counter. IC50 is determined by Linear regression analysis of the percent inhibition by JNJ-7706621.

Concentrations: 1 nM - 10 μM, dissolved in DMSO