Table 1.

Enzyme kinetics for UDP-Rha and UDP-Gal transport into proteoliposomes

		URGT1	URGT2	URGT3	URGT4	URGT5	URGT6
UDP-Rha*	Km, μM	87 (12)	61 (11)	40 (7)	37 (8)	17 (5)	33 (8)
	Vmax, pmol⋅min−1	742 (36)	1,411 (79)	1,023 (48)	631 (38)	188 (12)	264 (16)
	Vmax, nmol⋅s−1⋅mg−1	56 (2)	34 (2)	32 (2)	12 (1)	4 (0)	10 (0)
	Kcat, s−1	2.35	1.44	1.36	0.51	0.13	0.44
UDP-Gal	Km, μM	90 (22)	68 (16)	149 (37)	77 (19)	177 (53)	196 (96)
	Vmax, pmol⋅min−1	381 (33)	742 (57)	751 (78)	392 (32)	253 (33)	267 (59)
	Vmax, nmol⋅s−1⋅mg−1	28 (2)	19 (2)	24 (2)	8 (0)	4 (0)	10 (1)
	Kcat, s−1	1.21	0.76	1.00	0.32	0.18	0.44

^*For each combination of NST and nucleotide sugar, 20 data points with varying substrate concentrations (0.5–400 μM) were acquired. V_max and K_cat values were calculated using estimations of URGT abundance in the proteoliposome (Tables S4 and S5). SEs are shown in parentheses.