LDC000067 (LDC067) is a highly specific and selective CDK9 inhibitor with an IC50 value of 44±10 nM.

CDK9:44±10 nM

LDC000067 通过减少Ser2-P的水平，诱导p53激活，并在mESCs中导致细胞凋亡。此外，LDC067还能剂量依赖性地抑制P-TEFb依赖的细胞基因的de novo RNA合成。[1]

The fluorescence resonance energy transfer (FRET)-based LANCE Ultra KinaSelect Ser/Thr kit is used to determine IC50 values for various CDK inhibitors. Briefly, a specific ULight MBP peptide substrate (50 nM final concentration) is phosphorylated by a CDK-cyclin pair in buffer (50 mM HEPES-KOH pH 7.5, 10 mM MgCl2, 1 mM EGTA, 2 mM dithiothreitol) containing ATP at the concentration of the Km values of the individual kinases for 1 h at room temperature. Subsequently, phosphorylation is detected by addition of specific Eu-labelled anti-phospho-antibodies (2 nM), which upon binding to the phosphopeptide give rise to a FRET signal. FRET signals are then recorded[1].