TABLE 2.

Effect of unlabeled competitors on the uptake of l-[¹⁴C]carnitine and [¹⁴C]glycine betaine by T. halophila^a

Osmoprotectant	% Inhibition by:
	Glycine betaine	l-Carnitine	d-Carnitine	Choline
l-[14C]carnitine	70	85	89	59
[14C]glycine betaine	89	2	3	25

^aBacteria were grown in DM. Uptake assays were carried out as described in the text with either [¹⁴C]glycine betaine or l-[¹⁴C]carnitine (10 μM). Unlabeled competitors were added in 100-fold excesses. Results are given as the percent reductions of the uninhibited uptake rates, which were 2.0 and 3.4 nmol/min/mg (dry weight) for l-carnitine and glycine betaine, respectively. The results are the means of three independent experiments. The standard deviations were less than 5%.