Inhibition Assay: The inhibitory action of PDHK activity was indirectly evaluated by performing a kinase reaction in the presence of a test compound and measuring the residual PDH activity. For expression of hPDHK2 activity, Escherichia coli strain BL21(DE3) cells (Novagen) were transformed with the pET17b vector containing modified hPDHK2 cDNA. Escherichia coli were grown to an optical density 0.6 (600 nmol/L) at 30C. Protein expression was induced by the addition of 500 umol/L isopropyl-beta-thiogalactopyranoside. Escherichia coli were cultured at 30 C. for 5 hr and harvested by centrifugation. Resuspension of the Escherichia coli paste was disrupted by a microfluidizer. FLAG-Tagged protein was separated using FLAG affinity gel (Sigma). The gel was washed with 20 mmol/L N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid-sodium hydroxide (HEPES-NaOH), 500 mmol/L sodium chloride, 1% ethylene glycol, and 0.1% Pluronic F-68 (pH 8.0), and the binding protein was eluted with 20 mmol/L HEPES.
Inhbition Assay: For expression of hPDHK2 activity, Escherichia coli strain BL21(DE3) cells (Novagen) were transformed with the pET17b vector containing modified hPDHK2 cDNA. The Escherichia coli were grown to an optical density 0.6 (600 nmol/L) at 30 C. Protein expression was induced by the addition of 500 umol/L isopropyl-beta -thiogalactopyranoside. The Escherichia coli were cultured at 30 C. for 5 hr and harvested by centrifugation. Resuspension of the Escherichia coli paste was disrupted by a microfluidizer. FLAG-Tagged protein was purified using FLAG affinity gel. The gel was washed with 20 mmol/L HEPES-NaOH, 500 mmol/L sodium chloride, 1% ethylene glycol, and 0.1% Pluronic F-68 (pH 8.0), and the binding protein was eluted with 20 mmol/L HEPES-NaOH, 100 ug/mL FLAG peptide, 500 mmol/L sodium chloride, 1% ethylene glycol, and 0.1% Pluronic F-68 (pH 8.0). The eluted fractions containing FLAG-Tagged protein were pooled, dialyzed against 20 mmol/L HEPES-NaOH, 150 mmol/L sodium chloride.
Inhibition of N-terminal His6-SUMO tagged recombinant human PDK2 using [32P]-gamma-ATP assessed as decrease in incorporation of radioactivity into E1 protein incubated for 2 mins
Inhibition of N-terminal His6-SUMO tagged recombinant human PDK2 in presence of E1 protein and PDC core E2/E3BP incubated for 10 mins by titration assay