Table 1.
Summary of the key features of the different disulfide rebridging agents and the stability of the resultant conjugates.
| Reagent | Requires activation | Multifunctional | Conjugation yield [%][a] | Selectivity over unpaired Cys | Water soluble | Substrate | Stability of products |
|---|---|---|---|---|---|---|---|
| I | Y[b] | N | 20–40[d] | N | N | peptides, Fab, proteins, antibodies | cleaved by GSH, stable in serum |
| II | N | N | >80[e] | N | N | peptides, Fab, proteins, antibodies | cleaved in GSH, serum and mammalian cells |
| III | N | N | 70[e] | N | N | peptides, Fab | – |
| IV | N | N | quantitative[e] | Y | N | peptides | – |
| V | N | Y | quantitative[e] | N | N | peptides, Fab, antibodies | stable in GSH, serum and buffers |
| VI | Y[c] | N | 3–22[d] | N | N | peptides | – |
| VII | N | Y | 49[d] | N | Y | peptides, proteins | stable in buffers and serum |
[a] Based on conjugation yields to peptides. [b] Pre‐incubation for elimination of protecting group. [c] Requires photoactivation. [d] Isolated yields. [e] Determined from chromatography or spectroscopy.