TABLE 3.

Inhibition of succinate and orotate uptake by orotate, succinate, and malate^a

Inhibitor concn (mM)	Uptake [nmol (min · mg of protein)−1]
	Orotate (0.45 mM) inhibited by malate	Succinate (0.05 mM) inhibited by:
		Orotate	Malate
0.000	26.7	104.2	104.2
0.025	20.1
0.050	9.4		54.6
0.100	4.8	95.5
0.200		97.4

^aS. meliloti Rm8002 cultures were grown in M9 medium with 0.2% aspartate as a carbon source. The cultures were washed and resuspended in M9 medium without a carbon source. Assays were performed using 50 μM [¹⁴C]succinate and 450 μM [³H]orotate with the carbon substrate tested as inhibitor present at the concentrations shown.