Table 2.
Reactivities of substrates 3a, 5–7 upon treatment with peptide 19.
 | ||||
|---|---|---|---|---|
| Substrate | Equiv. | Overall yield | Product distribution | |
| Cys modified | Dual modified | |||
| 3a | 2a | 96% | 100% | ND |
| 5 | 2a | 72% | 100% | ND |
| 6 | 2a | 100% | 100% | ND |
| 7 | 2a | <1%b | 100% | ND |
| 3a | 10c | 100% | 100% | ND |
| 5 | 10c | 100% | 100% | ND |
| 6 | 10c | 100% | 29% | 71% |
| 7 | 10c | 100% | 100% | ND |
aReaction conditions: peptide 19 (0.2 mM) and 3a, 5, 6, or 7 (0.4 mM, 2 equiv.) were incubated for 5 min at 37 °C in HEPES buffer (20 mM, pH 7.5) containing 100 mM NaCl.
bThe overall yield increased to 15% when the reaction time was extended to 1 h.
cReaction conditions: peptide 19 (0.2 mM) and substrate (2 mM, 10 equiv.) were incubated for 1 h at 37 °C in HEPES buffer (20 mM, pH 7.5) containing 100 mM NaCl. Overall yields and product distributions were obtained by integration of ultra-performance liquid chromatography peaks. ND, not detected.