TABLE 3.

Comparison of CDP-ribitol synthase activities of different loci

Activity, enzyme, and substrateKm (μM)kcat (s−1)kcat/Km (M−1/s−1)
Reductase activity
    TarI′J′
        NADPH6.21 ± 1.070.41 ± 0.016.60 × 104
        Ribulose-5-P11.0 ± 0.93.73 × 104
    TarIJa
        NADPH6.74 ± 1.640.79 ± 0.061.17 × 105
        Ribulose-5-P28.5 ± 13.12.77 × 104
Cytidylyltransferase activity
    TarI′J′
        CTP38.7 ± 6.2066.7 ± 1.41.72 × 106
        Ribitol-5-P102.2 ± 9.66.53 × 105
    TarIJa
        CTP78.9 ± 33.276.8 ± 6.59.73 × 105
        Ribitol-5-P1,280 ± 3905.98 × 104
  • a Data for TarIJ were previously published by Pereira et al. (26).