Cysteine, even in low concentrations, induces transient amino acid starvation in Escherichia coli.

Cysteine, in concentrations down to 0.04 micrograms/ml, induces transient amino acid starvation in Escherichia coli growing in minimal medium. The duration depends on the concentration and is 5 min at 2 micrograms of cysteine per ml. At low cysteine concentrations, threonine and isoleucine almost completely abolish the starvation.