The common types of linkers used for the design of PROTACs
| Flexible linkers (n, m = 0, 1, 2, 3, 4, etc.) | Relatively rigid linkers | Click chemistry based linkers |
|---|---|---|
 alkane |  piperidine/benzene |  triazole |
 alkyne-alkane |  triazole-PEG | |
 PEG |  benzene |  (CLIPTAC) |
 PEG-alkane | ||
 amide |  azobenzene (photoswitchable) |