Table 1.
Cysteine persulfide (CysSSH) and cysteine polysulfide (CysSSSH) generated by the reaction of cysteine (CysSH) or cystine (CysSSCys) with sulfur donors.
| Na2S | CysSH (μM) | CysSSH (μM) | CysSSSH (μM) | |
|---|---|---|---|---|
| 100 μM CysSH | – | 74.8 ± 3.5 | N.D. | N.D. |
| + | 74.1 ± 2.5 | 2.2 ± 0.3 | N.D. | |
| 100 μM CysSSCys |
– | N.D. | N.D. | N.D. |
| + |
15.6 ± 0.1 |
22.2 ± 1.2 |
N.D. |
|
| Na2S4 | CysSH (μM) | CysSSH (μM) | CysSSSH (μM) | |
| 100 μM CysSH | – | 78.1 ± 1.8 | 2.0 ± 1.7 | N.D. |
| + | 7.9 ± 1.4 | 64.7 ± 0.7 | 34.3 ± 1.1 | |
| 100 μM CysSSCys | – | N.D. | N.D. | N.D. |
| + | 7.3 ± 0.6 | 65.7 ± 7.6 | 41.8 ± 3.7 | |
Note: One-hundred micromolar Na2S or Na2S4 was incubated with 100 μM CysSH or CysSSCys in 50 mM HEPES (pH 7.5) at 37°C for 30 min. The reaction mixture was incubated with 1 mM β-(4-hydroxyphenyl)ethyl (HPE) iodoacetamide at 37°C for 30 min to obtain HPE acetamide adducts, which were identified using LC/MS/MS and quantified using isotope-labeled internal standards. N.D., not detected.