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Updated: Apr 15, 2026
A High-Throughput Enzyme-Coupled Activity Assay to Probe Small Molecule Interaction with the dNTPase SAMHD1
Published on: April 16, 2021
Improved pharmacodynamic assay for dihydropyrimidine dehydrogenase activity in peripheral blood mononuclear cells
Dick Pluim1, Bart A W Jacobs, Maarten J Deenen
1Division of Molecular Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Background:
Dihydropyrimidine dehydrogenase (DPD) activity determination in peripheral blood mononuclear cells of DPD deficient patients was hitherto inaccurate due to hemoglobin (Hb) contamination. We developed an improved method for accurate measurement of DPD activity in patients.
Results:
DPD activity was determined by HPLC with online radioisotope detection using liquid scintillation counting. Hb was determined spectrophotometrically. Method accuracy and precision were significantly improved by using cumulative area of all peaks as IS. Peripheral blood mononuclear cell lysates from DPD deficient patients were highly contaminated with on average 23.3% (range 2.7-51%) of Hb resulting in up to twofold underestimated DPD activity. DPD activities were corrected for Hb contamination. The method was validated and showed good long-term sample stability.
Conclusion:
This method has increased specificity allowing accurate identification of DPD deficient patients.
