TABLE 2.

Inhibition of YtmJKLMN-dependent l-[¹⁴C]cystine uptake by different compounds

Competitora	% Inhibiton
l-Cystine	88 ± 4
l-Djenkolic acid	89 ± 2
dl-Cystathionine	80 ± 6
Seleno-dl-cystine	80 ± 3
S-Methyl-l-cysteine	73 ± 8
l-Histidine	45 ± 2
l-Methionine	40 ± 1
dl-Diaminopimelic acid	39 ± 1
dl-Lanthionine	32 ± 3
l-Glutamine	32 ± 4
l-Arginine	28 ± 2
dl-Homocystine	24 ± 2
l-Cysteine	<10
Oxidized glutathione	<10

^al-[¹⁴C]cystine was used at a concentration of 5 μM, and the unlabeled amino acids or sulfur compounds were present at a concentration of 50 μM. The initial l-[¹⁴C]-cystine uptake rate was measured.