Figure 5.
Effect of exogeneous polysulfides on CSE β-lyase activity toward cystine on the CSE mutants. Immobilized wild-type (WT) or indicated mutants CSE were incubated with 10 µM Na2S4 (A) or Cys-SSH synthesized by CSE/cystine (B), as described in Figure 4 at 37 °C for 30 min. CSE activity was measured by SSP4, as mentioned in Figure 4. Results are the mean ± SE of four to six independent experiments. **** p < 0.0001, ** p < 0.01, and * p < 0.05 when compared with the controls of each sample without polysulfides. n.s.: not significant.