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. Author manuscript; available in PMC: 2017 Jul 10.
Published in final edited form as: Mol Microbiol. 2009 Nov 17;75(1):29–45. doi: 10.1111/j.1365-2958.2009.06962.x

Table 6.

Summary of the uptake kinetics of the Cbc and Cho transporters.

Host Plasmid 1 Plasmid 2 SBP present [14C] Substrate Uptake kineticsa
Km Vmax
MKH13 pNcbcXWV None CbcX Choline 2.6 (0.66) 34.6 (2.2)
MKH13 pNcbcXWV None CbcX Betaine 24.2 (2.4) 11.6 (0.6)
MKH13 pNcbcWV pTPA3236 BetX Betaine 0.6 (0.16) 4.8 (0.18)
MKH13 pNchoXWV None ChoX Choline 1.8 (0.36) 1.2 (0.05)
PA5378::tn pNcbcWV None CaiXPAO1 Carnitine 24.2 (8.3) 3.8 (0.33)
a

The data were fit with the Michaelis–Menten equation (Fig. S4). The units for the apparent affinity constant (Km) are μM and for the maximal rate of uptake (Vmax) are nmol min−1 (mg protein)−1. Values shown are mean (SE) (n = 4).