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. Author manuscript; available in PMC: 2017 Jul 1.
Published in final edited form as: Mol Microbiol. 2016 May 2;101(1):62–77. doi: 10.1111/mmi.13372

Figure 1. Cystine stimulates rapid cysteine and sulfide excretion.

Figure 1

A. Total thiol excretion (circles) and hydrogen sulfide release (squares) from wild-type (MG1655) cells. Cells were cultured in glycerol medium with sulfate as the sole sulfur source. Solid symbols: 0.1 mM cystine (C2) was added at time zero. Open symbols: no addition. B. Rate of hydrogen sulfide release after cystine addition. Bar 3 represents sulfide release by cells that had been pre-cultured in medium containing 0.5 mM cystine. Time courses are representative of at least three independent experiments; error bars in all figures represent the standard deviation from three experiments. C. Wild-type and tryptophanase mutant (ΔtnaA) cells were cultured in glucose or glycerol medium, with 5 mM tryptophan supplements where indicated. After washing, sulfide production was measured immediately upon the addition of 0.5 mM cystine.