Table 1.

Specific activity of UMPK from parental and bolus 5-FU–resistant cell lines

SubstrateSpecific activity*
UMPFUMP
HCT-8/P0.14 ± 0.010.21
HCT-8/4hFU0.09 ± 0.020.17
HCT-8R/YALE0.09 ± 0.010.19

NOTE: Measurements ± SD shown above were recorded in the presence of 0.2 mmol/L UMP (biological triplicates) or 1.25 mmol/L FUMP as the substrate (biological duplicates). Samples were measured each time in triplicates.

  • *Specific activity of UMPK is expressed as μmol/mg/min.