TABLE 2.

Kinetic parameters for uridine uptake mediated by hCNT3 and mutants

	Apparent Kma	Vmaxa,b	Vmax:Kmb ratio
	μm	pmol/oocytes·min−1
E343Q	3.9 ± 0.7	1.7 ± 0.1 (0.09)	0.44 (0.27)
E343D	2.4 ± 0.3	3.2 ± 0.1 (0.16)	1.33 (0.75)
E343C	18.9 ± 0.9	7.2 ± 0.1 (0.28)	0.38 (0.16)
E519D	35.0 ± 1.6	40.1 ± 0.5 (2.41)	1.15 (0.75)
E519C	876 ± 57	39.0 ± 0.9 (1.45)	0.04 (0.02)
hCNT3	10.9 ± 0.7	23.4 ± 0.4 (1.00)	2.15 (1.00)

^a Data are from Fig. 5.

^b Values in parentheses are normalized relative to wild-type hCNT3 and adjusted for variations in cell surface expression (see Fig. 3 legend).